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Research needs for
the Battle against
Respiratory Viruses
(BRaVe)
Background document
2013
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World Health Organization 2013
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Acknowledgements
The World Health Organization (WHO) would like to thank the Wellcome Trust and the Fondation
Mrieux for their support for the two Informal Technical Consultations, in July and November 2012,
which contributed to the development of this research agenda.
Find out more on the Battle against Respiratory Viruses (BRaVe) initiative on the WHO web site:
www.who.int/influenza/patient_care/clinical/brave/en/index.html
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Contents
Acknowledgements iii
Abbreviations and acronyms v
Foreword vi
Introduction: needs for a research agenda 1
1. Defining the burden of disease of respiratory viral infections 6
2. Understanding disease pathogenesis and host dynamics of respiratory viral infections 12
3. Expanding treatment options for respiratory viral infections 16
4. Improving SARI diagnosis and diagnostic tests 20
5. Improving clinical management of SARI and CAP 23
6. Optimizing public health strategies 26
Full reference list 29
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Abbreviations and acronyms
ALRI acute lower respiratory infection
ARDS acute respiratory distress syndrome
ARI acute respiratory infections
CAP community-acquired pneumonia
COPD chronic obstructive pulmonary disease
CRP C-reactive protein
DALY disability adjusted life years
HCoV human coronavirus
Hib Haemophilus influenzae type B
HIV human immunodeficiency virus
HRV human rhinovirus
huMPV human metapneumovirus
ILI influenza-like illness
NAAT nucleic acid amplification test
PCT procalcitonin
PIV parainfluenza virus
RNA ribonucleic acid
RSV respiratory syncytial virus
RVI respiratory viral infection
SARI severe acute respiratory infection
WHO World Health Organization
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Foreword
Battle against respiratory viruses: the timing is right
Acute respiratory infections are a major global public health problem. Despite progress made in the 20th
century with the introduction of antibiotics, vaccines and (recently) antivirals, there are no specific
interventions for most respiratory infections of viral origin. These infections continue to cause frequent
morbidity, and sometimes cause severe outcomes including death, especially in developing countries.
Current practices for treating these illnesses (e.g. the frequent use of antibiotics) are ineffective and
often result in adverse consequences, including antimicrobial resistance.
The discovery of antiviral medicines in the late 20th century led to significant breakthroughs in the fight
against infectious diseases. Progress in molecular biology, genetic engineering and other disciplines has
enabled scientists to design and produce antivirals that target key viral proteins, or block critical
processes involved in viral replication. For example, there are effective antivirals for human
immunodeficiency virus (HIV), influenza, herpes, and hepatitis B and C viruses. These antiviral therapies
have been introduced widely into clinical practice in some countries, illustrating their potential value in
reducing morbidity and mortality. When these medications are combined with advances in diagnostics
tests and improvements in clinical management, it seems that effective treatment of respiratory viral
infections (RVIs) is a real possibility.
Although advances in the development of influenza vaccines and therapeutics have shown the potential
for mitigating the impact of seasonal and pandemic influenza, effective strategies that combine vaccines,
therapeutics and improved clinical management are currently lacking for most RVIs. Targeting such
infections will be a key challenge of the 21st century. We now have the research tools to develop
effective modalities against respiratory viruses. However, how can this new knowledge be rapidly and
effectively incorporated into public health strategies?
To succeed in the battle against respiratory viruses, we need to develop and implement a coherent,
integrated research agenda. Only through collective engagement can we assemble the ideas and
resources to find new weapons, particularly vaccines and therapeutics, against respiratory viruses, and
make them available to those in need. This research agenda will be the framework by which the research
and public health communities will identify gaps, and work together to fill those gaps.
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Introduction: needs for a research agenda (1-15)
Recent decades have seen many important studies on respiratory viral infections (RVIs), yet there is still
only a limited evidence base for understanding the burden of such infections, and for mitigating their
impact, and there are few effective pharmacologic interventions other than for influenza. We need to
know more about specific areas and to develop new interventions, to support the strategy of reducing
the health impacts of these pathogens, particularly the severe illnesses that cause hospitalizations and
deaths. The principal objectives of this research agenda are to:
identify the specific research needed to improve medical and public health responses to RVIs and
their sequelae over both the short-to-medium (15 years) and the medium-to-long (510 years)
term;
provide a framework reflecting public health research priorities for allocating research
resources, including studies applicable in under-resourced countries and those addressing areas
that have been relatively less studied (e.g. operational and social sciences research);
facilitate discussion, coordination and interactions among fundamental and clinical investigators
from both public and private sectors, funders, pharmaceutical industry representatives and
public health professionals;
highlight the need and the potential benefits of a multidisciplinary approach to addressing
knowledge gaps in prevention and treatment of RVIs.
This document will help in targeting funding towards priority areas, monitoring the progress in filling
knowledge gaps, and facilitating the development of evidence-based policies to prevent and mitigate
RVIs. The following section outlines important factors to take into account in considering the rationale
and scope of such a research agenda.
Respiratory viral infections are common and widespread
RVI is one of the most common health conditions globally, and has enormous but under recognized
impacts on public health. Everyone has experienced colds or influenza-like illness (ILI), and young
children average up to a dozen episodes per year. In addition to their high frequency, RVIs are major
causes of severe acute respiratory infection (SARI), which can lead to severe outcomes including
hospitalization and death (Box 1). RVIs are implicated in approximately 50% of community-acquired
pneumonia (CAP) in young children, over 90% of bronchiolitis cases in infants and young children seeking
medical attention, and over 90% of asthma exacerbations in children. In adults, they are implicated in
3050% of CAP, 80% or more of asthma exacerbations, and 2060% of exacerbations of chronic
obstructive pulmonary disease (COPD). In addition, RVIs predispose those infected to a range of
secondary bacterial infections including otitis media, sinusitis and CAP. Acute lower respiratory infections
(ALRIs) are estimated to cause 3.9 million deaths per year, and pneumonia alone is the leading single
cause of mortality in children under 5 years of age, with approximately 1.2 million children dying each
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year. Estimates indicate that about 99% of these deaths occur in developing countries, and 80% occur
out of hospital.
Direct and indirect costs of acute respiratory infections
Acute respiratory infections (ARIs) cause severe complications for patients, and impose an enormous
burden on communities. Communities can be directly affected; for example, through the need for
outpatient care and hospital services. One recent systematic analysis estimated that, in 2010,
14.9 million episodes of severe or very severe ALRI resulted in hospital admissions in young children
worldwide, although only 62% of children with severe ALRI were hospitalized. Communities can also be
indirectly affected; for example, ARIs are responsible each year for major losses in productivity, in part
due to absenteeism. ALRIs are the leading cause of burden of disease worldwide, accounting for 94.5
million disability adjusted life years (DALYs), equivalent to 6.2% of total DALYs.
Suboptimal management
Current management of RVIs is suboptimal in most countries, and often results in both use of ineffective
treatments and failure to use treatments of proven benefit. Because it is commonly thought that ARIs
are caused by bacteria, most such infections are treated with antibiotics. Even when a viral etiology is
diagnosed, the illness is unlikely to be treated with specific antivirals, because these are generally
unavailable, except possibly for influenza treatments in some settings.
Inappropriate antibiotic use
Inappropriate antibiotic use for RVIs is a widely prevalent problem that increases the risks for antibiotic
side-effects and emergence of antimicrobial resistance, as well as the cost of care. At the same time,
RVIs are major causes of secondary infections with bacteria. Measures undertaken to prevent and treat
the initiating RVIs could have major impacts on these adverse downstream consequences.
Innovative approaches targeting broad-spectrum pathogens are needed
With the availability of more sophisticated diagnostic tests, multiple respiratory viruses are now often
detected in ARIs, especially in children. Such observations raise questions about disease causation,
pathogenesis and the dynamics of infection with multiple agents; they also suggest that it would be
beneficial to consider innovative therapeutic approaches that do not focus on a single virus.
Complex mechanisms of disease
Host responses to RVIs are important in disease pathogenesis, but such responses are diverse across
population groups and are incompletely understood. Furthermore, mixed infections (both viralviral and
viralbacterial) increase the complexity of pathogenhost interactions. Improved therapeutic strategies
for RVIs will depend on a better understanding of the mechanisms of disease in different syndromes and
target populations.
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Syndromic approach
Except possibly during widespread outbreaks due to a specific virus (e.g. epidemic influenza), RVIs
cannot be addressed effectively or efficiently with a vertical approach that focuses on one agent at a
time from public health and clinical perspectives. A syndromic approach that addresses the pathogenesis,
prevention and optimal management of clinical problems such as CAP and other forms of SARI makes
most sense; it also allows for the introduction of technological advances in diagnostics and therapeutics
to those in greatest need.
Global health security threat
Respiratory viruses are pathogens that may have a major effect on global health security. In recent years,
we have witnessed the emergence and discovery of a number of new respiratory viruses including severe
acute respiratory syndrome (SARS) and other coronaviruses, avian H5N1 influenza and pandemic (H1N1)
2009 influenza, and there is a high likelihood of new respiratory viruses emerging that could cause
extensive disease and economic losses. The expectation is that the impact of these unpredictable events
will be mitigated to some extent by non-pharmaceutical interventions, specific antiviral and potentially
immunomodulatory therapies, and clinical management strategies effective for common RVIs. Studies in
the period between pandemics can generate evidence that will inform responses to both recognized and
novel RVI threats.
Treatments and vaccines
The treatment of RVIs will be an important complement to vaccination strategies directed at specific
respiratory viruses and their secondary bacterial complications; for example, at Streptococcus
pneumoniae and Haemophilus influenzae type B (Hib). Currently, we have vaccines for influenza,
although these are incompletely protective and underused, and require annual administration. A recent
position paper1 from a World Health Organization (WHO) Strategic Advisory Group of Experts (SAGE) on
immunization promotes maternal immunization against influenza to protect both mother and infants,
and this approach will be an important strategy to protect infants against respiratory syncytial virus (RSV)
and possibly other RVIs, once effective vaccines are available.
Despite years of investigation, there are as yet no effective vaccines for RSV, picornavirus or other
common respiratory viruses, except for several adenovirus serotypes. The large number of respiratory
virus families, types and serotypes means that effective vaccines for most such viruses are unlikely to be
1 Available at http://www.who.int/wer/2012/wer8747.pdf
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developed in the foreseeable future. Consequently, it makes sense to pursue an integrated approach to
RVIs by developing more effective therapeutics while continuing to pursue vaccine development for
particular threats for example, RSV and parainfluenza virus (PIV), and human metapneumovirus and
improving vaccines for influenza.
Mitigation
It is almost impossible to eradicate respiratory viruses because of their extraordinary diversity, complex
evolution and ability to be maintained in human populations (in part through transmission by mild or
subclinical infections). However, with the possible exception of measles infection, mitigation of the
impacts of respiratory viruses is now achievable.
Opportunities
In spite of the issues outlined above, we are at a turning point. The prospects of new antivirals, new
molecular diagnostics, novel vaccines and new management approaches offer opportunities to tackle
RVIs, but to exploit these opportunities, we need new weapons and strategies, and particularly, a focus
on scientific research. The overall goal for the proposed research agenda is to develop both the evidence
and the tools needed to strengthen public health actions and decision-making, in order to limit the
impact of acute RVIs and their consequences in both individuals and populations. In prioritizing research
activities, both data-driven hypotheses and feasibility should be considered; hence, the ranking of
particular projects is likely to evolve as better data or tools become available for addressing particular
questions.
The research needs for viral respiratory infections encompass six key areas, which are covered in this
document:
1. Defining the burden of disease
2. Understanding disease pathogenesis and host dynamics
3. Expanding treatment options
4. Improving SARI diagnosis and diagnostic tests
5. Improving clinical management of SARI and CAP
6. Optimizing public health strategies.
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References (Introduction)
1 World Health Organization. The global burden of disease: 2004 update. Geneva, WHO, 2008.
http://www.who.int/healthinfo/global_burden_disease/GBD_report_2004update_full.pdf
2 World Health Organization. The World health report 2002: Reducing risks, promoting healthy life.
Geneva, WHO, 2002.
3 World Health Organization/United Nations Childrens Fund. Global Action Plan for Prevention
and Control of Pneumonia (GAPP). Geneva, WHO/UNICEF, 2009.
http://www.who.int/maternal_child_adolescent/documents/fch_cah_nch_09_04/en/index.html
4 Welkers MR, Dunning J, Wong CH et al. Current research on respiratory viral infections: XIIth
International Symposium. Antiviral Therapy, 2012, 17(1 Pt B):227-253. PM:22311667
5 Welkers M, Sutherland T, Osterhaus AD et al. Current research on respiratory viral infections: XIII
International Symposium on Respiratory Viral Infections: part 1. Future Virology, 2011,
6(10):1155-1160.
6 Sutherland TC, Welkers MRA, Osterhaus ADME et al. Current research on respiratory viral
infections: XIII International Symposium on Respiratory Viral Infections: part 2. Future Virology,
2011, 6(11):1283-1288. http://dx.doi.org/10.2217/fvl.11.102
7 Scott JA, Wonodi C, Mosi JC et al. The definition of pneumonia, the assessment of severity, and
clinical standardization in the Pneumonia Etiology Research for Child Health Study. Clinical
Infectious Diseases, 2012, 54(Suppl 2):S109-S116.
http://cid.oxfordjournals.org/content/54/suppl_2/S109.abstract
8 Ruuskanen O, Lahti E, Jennings LC et al. Viral pneumonia. Lancet, 2011, 377(9773):1264-1275.
PM:21435708
9 Ranieri VM, Rubenfeld GD, Thompson BT et al. Acute respiratory distress syndrome: the Berlin
Definition. JAMA : The Journal of the American Medical Association, 2012, 307(23):2526-2533.
http://www.ncbi.nlm.nih.gov/pubmed/22797452
10 Osterhaus AD. New respiratory viruses of humans. The Pediatric Infectious Disease Journal, 2008,
27(10 Suppl):S71-S74. PM:18820582
11 Nair H, Simooes EA, Rudan I et al. Global and regional burden of hospital admissions for severe
acute lower respiratory infections in young children in 2010: a systematic analysis. Lancet, 2013.
PM:23369797
12 Levine OS, O'Brien KL, Deloria-Knoll M et al. The Pneumonia Etiology Research for Child Health
Project: a 21st century childhood pneumonia etiology study. Clinical Infectious Diseases, 2012,
54(Suppl 2):S93-101. http://www.ncbi.nlm.nih.gov/pubmed/22403238
13 Jartti T, Jartti L, Ruuskanen O et al. New respiratory viral infections. Current Opinion in
Pulmonary Medicine, 2012, 18(3):271-278. PM:22366993
14 Gilani Z, Kwong YD, Levine OS et al. A literature review and survey of childhood pneumonia
etiology studies: 2000-2010. Clinical Infectious Diseases, 2012, 54(Suppl 2):S102-108.
http://www.ncbi.nlm.nih.gov/pubmed/22403223
15 Anderson LJ, Baric RS. Emerging human coronaviruses disease potential and preparedness.
New England Journal of Medicine, 2012. PM:23075144
16 Nair H, Nokes DJ, Gessner BD et al. Global burden of acute lower respiratory infections due to
respiratory syncytial virus in young children: a systematic review and meta-analysis. Lancet, 2010,
375(9725):1545-1555. PM:20399493
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1. Defining the burden of disease of respiratory viral infections (16-31)
Respiratory illnesses, exemplified by pneumonia, are the leading cause of death from infectious diseases;
they account for approximately 20% of mortality in children under 5 years of age, particularly in
resource-limited settings. With improvements in diagnostic technologies, there has been an increase in
studies that specify the responsible viral pathogen. However, more research is needed to better estimate
the burden of RVI pathogens relative to bacterial or mixed etiologies in different settings.
These viruses also cause considerable morbidity in older children and adults, and mortality in older
adults and those with underlying conditions. For example, in the United States (US), 90% of seasonal
influenza and 78% of RSV-associated respiratory and circulatory deaths occur in adults aged 65 years and
older. Although many studies on RVIs focus on children under 5 years of age (Box 2) and elderly adults,
too little is known about the overall impact across the age spectrum. Similarly, population- or hospital-
based studies have highlighted the importance of specific RVIs such as influenza and RSV in causing
serious disease (Box 1).
The figures given in Box 1 do not include the contributions of other viruses to the global burden. Such
gaps in knowledge tend to hide the real burden of RVIs in the global population. Therefore, the
causative pathogens and particularly the contributions of RVIs need to be better characterized in
different clinical syndromes, settings and target populations.
Data on disease burden are unavailable from many countries, especially those that are under-resourced
and, at present, there is no globally integrated surveillance system for RVIs other than influenza.
Understanding the geographical patterns, seasonality and distributions of RVIs would allow for more
appropriate and targeted clinical management in situations where the burden of disease currently
remains hidden. Furthermore, the wider scale use of effective vaccines for viral infections (e.g. influenza)
and bacterial infections (e.g. Hib and pneumococcal conjugate) will probably lead to changes in the
etiologies and, perhaps, patterns of serious respiratory illnesses. For example, in older adults with high
uptake rates for influenza vaccine, the frequency of RSV-associated hospitalizations is comparable to
that caused by influenza.
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Box 1: Disease burden of respiratory infections (8, 16, 25, 32, 33)
A. Estimated global impacts of RVI in pneumonia and SARI:
CAP cases per year: 429.2 million
o 200 million cases of viral CAP per year
o Approximately 3.54 million deaths (7% of total annual mortality)
o Economic costs of US$ 17 billion per year in the US alone
CAP cases in children per year: 156 million
o 151 million CAP cases in developing countries
o RVI in 4367% of paediatric CAP cases
o 14.6 million SARI + severe CAP cases
o 1.4 million deaths in developing countries (>95% in developing countries)
B. Specific viral pathogens in children
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Box 2: Paediatric ALRI episodes in children under 5 years of age
Millions/year
ALRI, acute lower respiratory infection; Hib, Haemophilus influenzae type B; RSV, respiratory syncytial virus (16, 25, 26, 30)
Further information is needed on the role of RVIs in causing other clinical syndromes, in order to
improve strategies to reduce the overall morbidity and mortality of acute respiratory disease. Available
evidence indicates that respiratory viruses are the primary agents involved in multiple common
respiratory syndromes (e.g. rhinosinusitis, ILI, bronchiolitis, laryngotracheobronchitis, acute bronchitis,
exacerbations of asthma and COPD), and that they either directly cause other illnesses affecting the
upper respiratory tract (e.g. otitis media and sinusitis) and lower respiratory tract (e.g. pneumonia), or
foster secondary bacterial infections at these sites. In addition, some RVIs particularly influenza and
adenovirus have been associated with severe illnesses involving other organ systems (e.g.
encephalopathyencephalitis and myocarditis). RVIs also cause serious worsening or complications of
non-respiratory conditions (e.g. myocardial infarction, congestive heart failure, stroke and diabetes) that
contribute heavily to the burden of RVI-associated hospitalizations and mortality.
It appears that RVIs may sometimes also be associated with chronic sequelae, such as the development
of asthma. The role of viruses in the development of specific cancers is well-understood; for example, in
relation to the role of human papilloma virus (HPV) in cervical cancer, and of hepatitis viruses B and C in
liver cancers. However, little is known about any potential association between RVIs and malignancy.
Human adenoviruses are oncogenic in other animals, but are not known to be so in humans. Whatever
this situation, given that lung cancer is one of the leading non-communicable causes of death, further
knowledge could be of crucial importance.
0
5
10
15
20
25
30
35
Pneumococcal ALRI Hib ALRI RSV ALRI Influenza ALRI
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More research is needed to define the age-related burden of RVIs and what might be achieved with
more effective interventions. Both hospital-based and community-based surveillance systems are
required to provide quality data that link RVI and bacterial etiologies with outcomes. Where possible, the
synergies between increased surveillance and vaccine or antiviral probe studies are likely to improve the
overall strength of results.
Priority research questions
1.1 Assess the overall burden of disease generated by respiratory viruses, including their economic
consequences, by:
identifying the key respiratory viruses responsible for the major burden on health-care systems
in different settings (e.g. rural versus urban, tropical versus temperate), and seasons or times of
the year;
assessing the proportions of specific viral, bacterial and mixed-pathogen infections in pneumonia
and other serious acute lower respiratory infection (ALRI) syndromes in different age groups and
settings;
assessing the proportion of specific viral pathogen infections in exacerbation of other underlying
conditions, particularly asthma, COPD and cardiovascular disease (CVD);
assessing the interactions between acute respiratory viral infections and other infectious
diseases, including human immunodeficiency virus (HIV) and tuberculosis (TB).
1.2 Characterize the dynamics of respiratory virus transmission, the associated factors and their
impact at:
individual, household and institutional levels, and assess the utility of selected non-
pharmaceutical interventions;
population level (including factors in seasonality, interference and routes of transmission).
1.3 Assess the occurrence of respiratory virus infection and infectiousness in nosocomial settings,
and identify cost-effective means to prevent transmission.
1.4 Determine the longer term consequences of respiratory viral infections in infants and young
children (e.g. development of asthma or chronic lung disease).
1.5 Evaluate the potential reductions in burden of disease and the potential health-care effects
gained or realized in treating respiratory viral diseases.
1.6 Measure the comparative advantage (e.g. in terms of technical demands and costs) of reducing
disease burden with different combinations of preventive and therapeutic measures (e.g. individual
hygiene measures, vitamins, oxygen therapy, antiviral therapies and intensive care) for known
pathogens.
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References (Section 1)
8 Ruuskanen O, Lahti E, Jennings LC et al. Viral pneumonia. Lancet, 2011, 377(9773):1264-1275.
PM:21435708
16 Nair H, Nokes DJ, Gessner BD et al. Global burden of acute lower respiratory infections due to
respiratory syncytial virus in young children: a systematic review and meta-analysis. Lancet, 2010,
375(9725):1545-1555. PM:20399493
17 Dawood F, Iuliano A, Reed C et al. Estimated global mortality associated with the first 12 months
of 2009 pandemic influenza A H1N1 virus circulation: a modelling study. The Lancet Infectious
Diseases, 2012. http://www.thelancet.com/journals/laninf/article/PIIS1473-3099(12)70121-
4/abstract
18 Falsey AR, Hennessey PA, Formica MA et al. Respiratory syncytial virus infection in elderly and
high-risk adults. New England Journal of Medicine, 2005, 352(17):1749-1759. PM:15858184
19 Hammitt LL, Kazungu S, Morpeth SC et al. A preliminary study of pneumonia etiology among
hospitalized children in Kenya. Clinical Infectious Diseases, 2012, 54(Suppl 2):S190-S199.
PM:22403235
20 Liu L, Johnson HL, Cousens S et al. Global, regional, and national causes of child mortality: an
updated systematic analysis for 2010 with time trends since 2000. Lancet, 2012, 379(9832):2151-
2161. PM:22579125
21 Lunelli A, Rizzo C, Puzelli S et al. Understanding the dynamics of seasonal influenza in Italy:
incidence, transmissibility and population susceptibility in a 9-year period. Influenza and Other
Respiratory Viruses, 2012. PM:22694182
22 Mermond S, Zurawski V, D'Ortenzio E et al. Lower respiratory infections among hospitalized
children in New Caledonia: a pilot study for the Pneumonia Etiology Research for Child Health
project. Clinical Infectious Diseases, 2012, 54(Suppl 2):S180-S189. PM:22403234
23 Miller EK, Lu X, Erdman DD et al. Rhinovirus-associated hospitalizations in young children. The
Journal of Infectious Diseases, 2007, 195(6):773-781. PM:17299706
24 Murata Y. Respiratory syncytial virus infection in adults. Current Opinion in Pulmonary Medicine,
2008, 14(3):235-240. PM:18427247
25 Nair H, Brooks WA, Katz M et al. Global burden of respiratory infections due to seasonal
influenza in young children: a systematic review and meta-analysis. Lancet, 2011,
378(9807):1917-1930. PM:22078723
26 O'Brien KL, Wolfson LJ, Watt JP et al. Burden of disease caused by Streptococcus pneumoniae in
children younger than 5 years: global estimate. Lancet, 2009, 374(9693):893-902. PM:19748398
27 Shrestha SS, Swerdlow DL, Borse RH et al. Estimating the burden of 2009 pandemic influenza A
(H1N1) in the United States (April 2009April 2010). Clinical Infectious Diseases, 2011, 52(Suppl
1):S75-S82. PM:21342903
28 Thompson WW, Shay DK, Weintraub E et al. Mortality associated with influenza and respiratory
syncytial virus in the United States. JAMA : The Journal of the American Medical Association,
2003, 289(2):179-186. PM:12517228
29 van Asten L, van den Wijngaard C, van PW et al. Mortality attributable to 9 common infections:
Significant effect of influenza A, respiratory syncytial virus, influenza B, norovirus, and
parainfluenza in elderly persons. The Journal of Infectious Diseases, 2012. PM:22723641
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30 Watt JP, Wolfson LJ, O'Brien KL et al. Burden of disease caused by Haemophilus influenzae type b
in children younger than 5 years: global estimates. Lancet, 2009, 374(9693):903-911.
PM:19748399
31 Wonodi CB, Deloria-Knoll M, Feikin DR et al. Evaluation of risk factors for severe pneumonia in
children: The Pneumonia Etiology Research for Child Health Study. Clinical Infectious Diseases,
2012, 54(Suppl 2):S124-S131. http://cid.oxfordjournals.org/content/54/suppl_2/S124.abstract
32 World Health Organization. World health statistics. Geneva, WHO, 2012.
http://www.who.int/gho/publications/world_health_statistics/2012/en/index.html
33 Hall CB, Weinberg GA, Iwane MK et al. The burden of respiratory syncytial virus infection in
young children. New England Journal of Medicine, 2009, 360(6):588-598.
http://www.ncbi.nlm.nih.gov/pubmed/19196675
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2. Understanding disease pathogenesis and host dynamics of respiratory
viral infections (34-49)
To develop more effective treatments and public health interventions, we need better understanding of
the mechanisms by which respiratory viruses are transmitted and cause disease. Little is known about
the pathogenesis of RVIs, and it is likely that interactions between virus, host and environment vary
among specific pathogens and among key patient groups. For example, viral replication patterns and
innate immune responses differ between mild upper respiratory infections and severe lower respiratory
infections, and between patient groups at high risk of complications (e.g. infants, pregnant women,
elderly adults and immunocompromised hosts). Data on the kinetics of viral replication would be a useful
first step in determining infection control measures. Disease severity following infection depends on
multiple factors, including pre-existing immunity, host genetic factors and underlying conditions, viral
replication kinetics in the upper and lower respiratory tract, inefficient or aberrant host innate and
adaptive immune responses triggered by viral replication, environmental conditions, and virulence
factors related to mutations in key viral proteins.
Specific data on viral replication dynamics and host pro-inflammatory and immune responses (especially
in the lower respiratory tract) in key patient groups are important to determine the nature, timing
(initiation and cessation), and potency of candidate immunomodulatory and host-directed therapeutic
interventions. Such data may also serve to discourage use of potentially harmful interventions. For
example, systemic corticosteroids have been commonly used in management of RSV-associated
bronchiolitis and of influenza-associated acute lung injury or acute respiratory distress syndrome (ARDS).
However, available data do not indicate benefit and, in the case of influenza, actually appear to indicate
harm in terms of prolongation of viral replication, adverse drug effects, and increased risks of nosocomial
infections and mortality.
Elevated temperatures have been associated with host-defense immunological mechanisms against
influenza infection, such as the proliferative response of lymphocytes or the increased production and
activity of cytokines. Animal models reveal an increased risk of mortality associated with antipyretics
during influenza infection. Although antipyretics are widely used in humans, there is little evidence on
their potential adverse events. More research on these practices is therefore important.
Viruses and (commensal) bacteria are often present together in the respiratory tract, but relatively little
is known about their interplay and how this affects transmission and disease pathogenesis. The
importance of bacterial pneumonias and, sometimes, bloodstream infections following influenza is well
documented. Various mechanisms have been implicated in promoting secondary bacterial infections,
including increased bacterial adherence, altered tracheobronchial clearance, inhibition of functions of
polymorphonuclear leukocytes (PMN) and macrophages, anergy of pattern recognition receptors, and
viral virulence factors such as PB1-F2. Animal model studies of pneumococcal pneumonia following
influenza suggest that antiviral therapy can lessen disease severity and that some commonly used
antibiotics might enhance adverse inflammatory responses.
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The frequency of bacterial complications and the mechanisms involved following other RVIs are less well
studied. Furthermore, many common respiratory viruses such as human rhinovirus (HRV), RSV and
human coronavirus (HCoV) are associated with mixed viralbacterial infections involving sites in the
upper respiratory tract (e.g. otitis media and sinusitis), in part related to altered Eustachian tube function
and inadequate sinus drainage. Further understanding of the processes involved in secondary bacterial
infections may help to improve strategies for prevention and management.
Sensitive methods for nucleic acid detection have led to the frequent detection of multiple viral
pathogens in respiratory samples, especially in infants and young children. Two or three respiratory
viruses are detected in 1020% of paediatric pneumonia cases (Box 3). The pathogenic consequences of
these viral co-infections have not yet been clarified, but may depend on the particular viruses involved,
the timing of acquisition (concurrent or sequential), the interval between acquisition, and host factors.
Improved understanding of virushost interactions in key patient groups is fundamental to developing
rationally designed therapeutics and vaccines. This includes understanding the basis of transmission and
the pathology associated with infection, as well as the basis of mechanisms and consequences of viral
and bacterial co-infections. Complementary basic and clinical research approaches will be required.
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Priority research questions
2.1 Understand the interactions of different respiratory viruses with host-cell pathways, and their
roles in pathogenesis and as potential targets for intervention.
2.2 Characterize viral and bacterial replication dynamics and host immune responses in the upper
and lower respiratory tracts during infection in key patient groups.
2.3 Understand the interplay between viral, bacterial (including the human microbiome) and host
factors in disease pathogenesis.
2.4 Understand the effect of the virus on immune responses, including the basis of protection and
the role of viruses in inhibiting effective responses.
2.5 Understand the pathogen, host and environmental factors and mechanisms that determine viral
and bacterial transmission.
2.6 Clarify the issue of disease causation for different viruses (e.g. frequency of subclinical infection,
and significance of viral ribonucleic acid [RNA] detection), and the contributory roles of specific
pathogens during infection with multiple agents.
2.7 Identify host genetic factors that determine susceptibility to respiratory viral infections and the
severity of such infections, and assess the implications for therapeutic interventions.
2.8 Determine the underlying mechanisms for established major risk factors in the host (e.g.
pregnancy, obesity, smoking and comorbidities) and the environment (e.g. passive smoking and indoor
air pollution) associated with increased disease severity.
2.9 Promote efforts to obtain etiology and pathogenesis data from fatal cases, through strategic use
of limited postmortem sampling (e.g. needle biopsies of affected and unaffected lungs).
References (Section 2)
22 Mermond S, Zurawski V, D'Ortenzio E et al. Lower respiratory infections among hospitalized
children in New Caledonia: a pilot study for the Pneumonia Etiology Research for Child Health
project. Clinical Infectious Diseases, 2012, 54(Suppl 2):S180-S189. PM:22403234
34 Agrati C, Gioia C, Lalle E et al. Association of profoundly impaired immune competence in H1N1v-
infected patients with a severe or fatal clinical course. The Journal of Infectious Diseases, 2010,
202(5):681-689. PM:20670171
35 Bezerra PG, Britto MC, Correia JB et al. Viral and atypical bacterial detection in acute respiratory
infection in children under five years. PloS One, 2011, 6(4):e18928. PM:21533115
36 Collins PL, Graham BS. Viral and host factors in human respiratory syncytial virus pathogenesis.
Journal of Virology, 2008, 82(5):2040-2055. PM:17928346
37 El Saleeby CM, Bush AJ, Harrison LM et al. Respiratory syncytial virus load, viral dynamics, and
disease severity in previously healthy naturally infected children. The Journal of Infectious
Diseases, 2011, 204(7):996-1002. PM:21881113
38 Everitt AR, Clare S, Pertel T et al. IFITM3 restricts the morbidity and mortality associated with
influenza. Nature, 2012, 484(7395):519-523. PM:22446628
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Research needs for the Battle against Respiratory Viruses (BRaVe) 15 | P a g e
39 Eyers S, Weatherall M, Shirtcliffe P et al. The effect on mortality of antipyretics in the treatment
of influenza infection: systematic review and meta-analysis. Journal of the Royal Society of
Medicine, 2010, 103(10):403-411. PM:20929891
40 Gern JE. The ABCs of rhinoviruses, wheezing, and asthma. Journal of Virology, 2010, 84(15):7418-
7426. PM:20375160
41 Horby P, Sudoyo H, Viprakasit V et al. What is the evidence of a role for host genetics in
susceptibility to influenza A/H5N1? Epidemiology and Infection., 2010, 138(11):1550-1558.
PM:20236573
42 Jagger BW, Wise HM, Kash JC et al. An overlapping protein-coding region in influenza A virus
segment 3 modulates the host response. Science, 2012. PM:22745253
43 Lee N, Chan PK, Wong CK et al. Viral clearance and inflammatory response patterns in adults
hospitalized for pandemic 2009 influenza A(H1N1) virus pneumonia. Antiviral Therapy, 2011,
16(2):237-247. PM:21447873
44 Lee N, Wong CK, Chan PK et al. Cytokine response patterns in severe pandemic 2009 H1N1 and
seasonal influenza among hospitalized adults. PloS One, 2011, 6(10):e26050. PM:22022504
45 Melendi GA, Laham FR, Monsalvo AC et al. Cytokine profiles in the respiratory tract during
primary infection with human metapneumovirus, respiratory syncytial virus, or influenza virus in
infants. Pediatrics, 2007, 120(2):e410-e415. PM:17671045
46 Mizgerd JP. Acute lower respiratory tract infection. New England Journal of Medicine, 2008,
358(7):716-727. PM:18272895
47 Peiris JS, Cheung CY, Leung CY et al. Innate immune responses to influenza A H5N1: friend or foe?
Trends in Immunology, 2009, 30(12):574-584. PM:19864182
48 Sullivan JE, Farrar HC. Fever and antipyretic use in children. Pediatrics, 2011, 127(3):580-587.
PM:21357332
49 Zaas AK, Chen M, Varkey J et al. Gene expression signatures diagnose influenza and other
symptomatic respiratory viral infections in humans. Cell host and Microbe, 2009, 6(3):207-217.
PM:19664979
50 Pavia AT. Viral infections of the lower respiratory tract: old viruses, new viruses, and the role of
diagnosis. Clinical Infectious Diseases, 2011, 52(Suppl 4):S284-289.
http://www.ncbi.nlm.nih.gov/pubmed/21460286
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3. Expanding treatment options for respiratory viral infections (51-61)
A number of antivirals have been tested for treatment of RVIs; they include interferons, ribavirin,
amantadine, oseltamivir, zanamivir, antibody preparations for RSV and capsid-binding anti-HRV
compounds. The agents of proven therapeutic value are mainly those for influenza, such as oseltamivir,
which reduces disease severity and mortality. For example, during the (H1N1) 2009 pandemic in Japan,
the combination of early diagnosis, rapid testing and oseltamivir treatment, in addition to other factors,
resulted in the lowest mortality rate in the world, with no influenza deaths in pregnant women. However,
oseltamivir fails to adequately control viral replication in some patients, and resistance is emerging as a
problem H1N1 virus resistant to oseltamivir was circulating globally in 200709. Consequently, more
potent antiviral combinations, especially for seriously ill persons, are needed.
In addition to oseltamivir, other neuraminidase inhibitors, including intravenous and long-acting inhaled
formulations, are in clinical development, as are several agents with novel mechanisms of anti-influenza
action (e.g. DAS181, favipiravir, nitazoxanide and AVI-7100). Recent reports of results with inhaled
interferon-beta or an oral anti-HRV inhibitor are promising, with reduced rhinovirusassociated cold
symptoms and modulated risk of exacerbations in asthmatic patients. However, there are no drugs to
treat most RVIs, and the relatively high cost of anti-influenza agents hinders their optimal use, especially
in low- and middle-income countries.
Most antiviral drugs have been developed by identifying viral proteins that can be inhibited by small
molecular chemical entities or, in some instances, larger biotherapeutics. Consequently, most approved
antiviral drugs are highly specific for a particular virus or family of viruses (e.g. neuraminidase inhibitors
and adamantanes for influenza). The advantage of this strategy is selectivity, and it may lower the risk of
adverse host effects. The disadvantages are a limited antiviral spectrum, the risk of antiviral resistance
and limitations on the number of virus-encoded proteins with properties suitable for developing
pharmaceutically acceptable inhibitors.
Recent non-clinical studies using ribonucleic acid interference (RNAi) screens have examined the cellular
interactions of selected viruses, and determined that large numbers of host-cell functions are essential
to viral replication. Through this approach, host-directed therapies could be identified and used as short-
term inhibitors. In some instances, a particular host function or pathway is required for the replication of
many different viruses. This raises the possibility of developing antiviral drugs with broad-spectrum
activity.
A related area of research is understanding and modulating host innate immune and other inflammatory
responses to RVIs. These host responses are thought to account for much of the symptomatology of
acute RVIs, and, in some cases, contribute to tissue damage in key target organs like the lung. However,
more information is needed on RVI pathogenesis in different syndromes and patient groups. Some of the
pathways involved in these host responses are also those necessary for efficient viral replication.
Consequently, a drug has the potential to inhibit viral replication and potentially deleterious host
responses. There is also evidence of inadequate host responses in some RVIs (e.g. deficient interferon
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Research needs for the Battle against Respiratory Viruses (BRaVe) 17 | P a g e
responses in severe influenza pneumonia and perhaps RSV infections), which may open the possibility of
therapeutic intervention.
For some RVIs, prophylaxis is a viable option. Vaccination is an effective intervention for influenza,
although protective efficacy varies across patient groups and seasons, and vaccine availability may be
severely limited during a pandemic. Influenza antivirals are effective for chemoprophylaxis but
prophylactic use has been limited by cost and, in some target groups, concerns about the emergence of
resistance. For RSV, there is currently no vaccine or chemoprophylaxis, but passive immunization with
either human immunoglobulin or anti-F monoclonal antibody (e.g. palivizumab) during the RSV season is
partially protective in high-risk groups such as preterm infants. The available RSV interventions are too
expensive for broad use in developing countries, although imminent patent expiry may mean more
affordable versions of these products will be developed.
More research is needed to expand treatment options across the range of respiratory viral pathogens.
Data from seasonal burden-of-disease studies indicate that therapeutics for RSV and HRV infections
should be prioritized. New data from burden-of-disease and pathogenesis studies will also inform
prioritization. Antiviral resistance and human pharmacokinetics, including pharmacokinetic
pharmacodynamic relationships and drugdrug interactions for combinations, are cross-cutting issues
that need to be integrated in therapeutic development strategies.
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Priority research questions
3.1 Develop and test new antivirals and combinations of antivirals for major respiratory viral
pathogens according to their burden:
given current burden-of-disease data, prioritize the development of inhibitors for RSV and
rhinovirus infections;
given concerns about resistance to adamantane and neuraminidase inhibitors (NAIs), also
prioritize development of influenza inhibitors with novel mechanisms of action;
test the effectiveness of combination antiviral therapy in seriously ill, hospitalized patients with
influenza.
3.2 Develop novel antiviral modalities and test their effectiveness in relevant target populations;
test:
existing broad-spectrum antivirals (e.g. favpiravir and nitazoxanide);
broad-spectrum antivirals against emerging viral threats (e.g. interferons for novel coronavirus);
host pathway-directed therapies, particularly those potentially inhibiting replication of multiple
viral pathogens.
3.3 Determine the host factors (e.g. genetic differences in drug metabolism) and drug
pharmacokinetic factors that predict responses to antiviral treatment, risk of adverse events and risk of
emergence of resistance.
3.4 Optimize dose regimens of existing antivirals for particular target populations.
3.5 Assess the effectiveness and safety of low-cost adjunctive therapies with regard to potential to
modulate the course of infection and of illness, including host immune responses. Therapies to test
include:
vitamin and mineral supplements (e.g. probiotics, selenium, vitamin A, vitamin D and zinc),
especially in populations with deficiencies;
immunomodulatory interventions (e.g. corticosteroids, cyclo-oxygenase 2 inhibitors, glitazones
and statins), particularly for treatment in conjunction with antivirals in severe illness;
commonly used medications for symptom relief (e.g. non-steroidal anti-inflammatory drugs
NSAIDs).
3.6 Define the criteria for using combinations of treatments, especially for antivirals and antibiotics,
and for antivirals and immunomodulatory agents.
3.7 Develop affordable prophylactic interventions (e.g. vitamin and mineral supplements) for high-
risk groups, to determine the ability of such interventions to reduce the vulnerability of patients before
infection.
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References (Section 3)
51 DeVincenzo JP. The promise, pitfalls and progress of RNA-interference-based antiviral therapy
for respiratory viruses. Antiviral Therapy, 2012, 17(1 Pt B):213-225. PM:22311654
52 Geevarghese B, Simoes EA. Antibodies for prevention and treatment of respiratory syncytial
virus infections in children. Antiviral Therapy, 2012, 17(1 Pt B):201-211. PM:22311607
53 Hayden FG. Experimental human influenza: observations from studies of influenza antivirals.
Antiviral Therapy, 2012, 17(1 Pt B):133-141. PM:22311616
54 Ludwig S. Disruption of virus-host cell interactions and cell signaling pathways as an anti-viral
approach against influenza virus infections. Biological Chemistry, 2011, 392(10):837-847.
PM:21823902
55 McCarthy MK, Weinberg JB. Eicosanoids and respiratory viral infection: coordinators of
inflammation and potential therapeutic targets. Mediators of Inflammation, 2012, 2012:236345.
PM:22665949
56 Nguyen HT, Fry AM, Gubareva LV. Neuraminidase inhibitor resistance in influenza viruses and
laboratory testing methods. Antiviral Therapy, 2012, 17(1 Pt B):159-173. PM:22311680
57 Nichols WG, Peck Campbell AJ, Boeckh M. Respiratory viruses other than influenza virus: impact
and therapeutic advances. Clinical Microbiol Reviews, 2008, 21(2):274-290, table. PM:18400797
58 Renaud C, Englund JA. Antiviral therapy of respiratory viruses in haematopoietic stem cell
transplant recipients. Antiviral Therapy, 2012, 17(1 Pt B):175-191. PM:22311587
59 Shaw ML. The host interactome of influenza virus presents new potential targets for antiviral
drugs. Reviews in Medical Virology, 2011, 21(6):358-369. PM:21823192
60 Smith SB, Dampier W, Tozeren A et al. Identification of common biological pathways and drug
targets across multiple respiratory viruses based on human host gene expression analysis. PloS
One, 2012, 7(3):e33174. PM:22432004
61 Tan EL, Ooi EE, Lin CY et al. Inhibition of SARS coronavirus infection in vitro with clinically
approved antiviral drugs. Emerging Infectious Diseases, 2004, 10(4):581-586. PM:15200845
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4. Improving SARI diagnosis and diagnostic tests (62-73)
RVIs are often unrecognized or ignored by clinicians, especially in developing countries, because of the
lack of rapid, inexpensive and reliable diagnostic tests, and the sense that no effective treatments are
available. To reduce the burden of RVIs, good diagnostic tests are needed, especially at the point of care.
Such tests would raise awareness of health-care workers about the viral etiology of the disease, guide
therapeutic choices and improve clinical management of RVIs.
Establishing the etiology of RVIs remains challenging, although new molecular technologies in
particular multiplex nucleic acid amplification tests (NAATs) are promising tools that can be used in
developing country settings. Compared to older tests, NAATs are better able to detect fastidious or non-
cultivable pathogens such as human metapneumovirus (huMPV), HCoV and HRV, or low quantities of
pathogens, but results can be difficult to interpret. Detecting viral RNA at the same time as pneumonia
or SARI may indicate direct causality (e.g. bronchiolitis or viral pneumonia), indirect or predisposing
causality (e.g. secondary bacterial or mixed infection) or an unrelated incidental finding. The high
prevalence of RNA for some respiratory viruses (e.g. HRV) in apparently healthy infants and young
children (detected by qualitative assays) may represent subclinical or mild infections, or prolonged
excretion after a recent illness. Determining background rates in control groups and quantitative RNA
levels in the respiratory tract or other sites (e.g. blood) may therefore be important.
In resource-limited settings, other issues related to NAATs include high start-up equipment costs,
sensitivity to extreme environmental conditions, and access to reliable power supply, reagents and
technical support. Studies of the etiology of paediatric pneumonia (e.g. using RNA detection methods)
will help in assessing some of these issues; such studies include the Pneumonia Etiology Research for
Child Health (PERCH) and the Global Approach for Biological Research on Infectious Epidemics in Low
income countries (GABRIEL).
Another area of active investigation is the measurement of biomarkers that may distinguish patients
with bacterial etiologies from those with viral or non-bacterial etiologies. Such biomarkers may help to
inform clinical decision-making. For example, serum procalcitonin (PCT) levels are elevated in patients
with bacterial pneumonia and septic shock, whereas they are generally not elevated in those with RVI,
unless there is secondary bacterial or mixed infection. PCT levels are more dynamic and increase faster
than other markers such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels in
bacterial infections. Rapid decreases in PCT appear to indicate prompt response to antibiotic therapy and
the potential for short antibiotic courses, but confirmatory studies are needed. Other studies suggest
that, in patients with influenza, CRP levels may be informative for assessing risk of progression or
bacterial complications.
Improved diagnostic methods over the past decade present a much more complicated picture of
respiratory infections. Work on diagnostic tests should focus on three main goals: improving clinical
management of patients; assisting surveillance and burden-of-disease determinations; and supporting
other areas of RVI research (e.g. the evaluation of novel therapeutics). Platforms applicable to multiple
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Research needs for the Battle against Respiratory Viruses (BRaVe) 21 | P a g e
pathogens and sample types should be developed as a priority. The priority research questions for this
section are aimed at better assessment and understanding of the complexity of respiratory infection.
Priority research questions
4.1 Develop reference reagents and performance standards to promote diagnostic development and
to assure accurate test performance.
4.2 Strengthen comprehensive characterization of respiratory specimens to inform diagnostic test
development, validation and interpretation, through deep sequencing and public posting of genetic and
epidemiologic findings.
4.3 Evaluate existing specimen collection techniques and devices, and develop new methods that
improve diagnosis of respiratory diseases.
4.4 Develop simple, accurate, low-cost nucleic acid amplification tests (NAATs) for acute respiratory
diseases.
4.5 Identify early biomarkers of the etiology and prognosis of pneumonia and ALRIs.
4.6 Develop protocols, algorithms and tools for rapid identification and characterization of emerging
respiratory infections.
References (Section 4)
62 Zimmerman O, Rogowski O, Aviram G et al. C-reactive protein serum levels as an early predictor
of outcome in patients with pandemic H1N1 influenza A virus infection. BMC Infectious Diseases,
2010, 10:288. PM:20920320
63 Murdoch DR, O'Brien KL, Driscoll AJ et al. Laboratory methods for determining pneumonia
etiology in children. Clinical Infectious Diseases, 2012, 54(Suppl 2):S146-S152. PM:22403229
64 Loens K, Van HL, Malhotra-Kumar S et al. Optimal sampling sites and methods for detection of
pathogens possibly causing community-acquired lower respiratory tract infections. Journal of
Clinical Microbiology, 2009, 47(1):21-31. PM:19020070
65 Lieberman D, Shimoni A, Keren-Naus A et al. Identification of respiratory viruses in adults:
nasopharyngeal versus oropharyngeal sampling. Journal of Clinical Microbiology, 2009,
47(11):3439-3443. PM:19726607
66 Hammitt LL, Murdoch DR, Scott JA et al. Specimen collection for the diagnosis of pediatric
pneumonia. Clinical Infectious Diseases, 2012, 54(Suppl 2):S132-S139. PM:22403227
67 Ginocchio CC. Strengths and weaknesses of FDA-approved/cleared diagnostic devices for the
molecular detection of respiratory pathogens. Clinical Infectious Diseases, 2011, 52(Suppl
4):S312-S325. PM:21460290
68 Gilbert DN. Procalcitonin as a biomarker in respiratory tract infection. Clinical Infectious Diseases,
2011, 52(Suppl 4):S346-S350. PM:21460294
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69 Chartrand C, Leeflang MM, Minion J et al. Accuracy of rapid influenza diagnostic tests: a meta-
analysis. Annals of internal medicine, 2012, 156(7):500-511.
http://www.ncbi.nlm.nih.gov/pubmed/22371850
70 Bhat N, O'Brien KL, Karron RA et al. Use and evaluation of molecular diagnostics for pneumonia
etiology studies. Clinical Infectious Diseases, 2012, 54(Suppl 2):S153-S158. PM:22403230
71 Bartlett JG. Diagnostic tests for agents of community-acquired pneumonia. Clinical Infectious
Diseases, 2011, 52(Suppl 4):S296-S304. PM:21460288
72 American Academy of Microbiology. Bringing the lab to the patient: Developing point-of-care
diagnostics for resource limited settings. American Society for Microbiology, 2012.
http://www.finddiagnostics.org/resource-
centre/reports_brochures/bringing_the_lab_to_the_patient_2012.html
73 An unmet medical need: rapid molecular diagnostics tests for respiratory tract infections. Clinical
Infectious Diseases, 2011, 52(Suppl 4):S384-S395. PM:21460300
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5. Improving clinical management of SARI and CAP (50, 74-87)
In all resource settings, timely and appropriate clinical management can reduce morbidity and,
potentially, mortality related to RVIs. Better evaluation algorithms, diagnostics, and safe and effective
treatments are needed. Identifying valid prognostic markers and scoring systems can help to determine
the correct type and level of care. Supportive-care interventions, such as oxygenation, rehydration and
(sometimes) non-invasive ventilation, may provide benefit in ALRI by preventing progression to severe
illness and death, especially in settings lacking modern intensive care capacities. However, there is an
insufficient evidence base for such basic supportive-care measures.
Some well-known effective interventions, such as oxygen therapy, are rarely used in many developing
countries. Every year, 1120 million children are admitted with pneumonia. At least 13.3% (1.5
2.7 million) have hypoxemia, which contributes to the more than 1.2 million deaths caused by
pneumonia. Investment in oxygen systems to improve detection and management of hypoxemia should
be part of health system support. However, there are many obstacles to using oxygen therapy. Scientific
evidence is still lacking on the efficacy and cost-effectiveness of oxygen use in low-resource settings. This
has prevented the publication of guidelines on oxygen use using the Grading of Recommendations
Assessment, Development and Evaluation (GRADE) approach1 and the inclusion of oxygen on the global
essential list of medicines2. Also, despite advances in technology for oxygen concentrators and pulse
oximeters, and the increased affordability of such devices, more innovation is needed to reach resource-
limited settings and ensure sustainable use of these techniques.
In many practice settings, antibiotics (including over-the-counter ones obtained by patients or their
family members) are frequently used to treat probable RVIs. Inappropriate antibiotic use drives
resistance; it also raises the costs of care and the risk of adverse events. Clinicians are often poorly
informed on the appropriate use of available antivirals and on the avoidance of interventions such as
systemic corticosteroids that might cause harm in certain RVIs (e.g. influenza and viral pneumonia).
More research is needed to improve clinical management strategies, and to help health professionals
adopt new attitudes to and practices in RVIs. The rapid communication of clinical management guidance
during the pandemic (H1N1) 2009 appeared to affect practice patterns. However, follow-up studies have
found reversion to pre-pandemic patterns; for example, delayed antiviral use for severe influenza in
1 http://www.who.int/kms/guidelines_review_committee/en/index.html
2 http://www.who.int/medicines/services/essmedicines_def/en/index.html
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multiple countries, and associated increases in mortality. These examples show that it is crucial to forge
and sustain a paradigm shift regarding health-care workers beliefs and practices on clinical management
of RVIs.
Better integration of research activities and clinical practice is crucial in developing the most relevant
evidence base for policy decisions. All ages and settings must be considered in improving clinical
management practices. Clinical research can be undertaken, with designs ranging from observational
studies to randomized controlled trials (traditional or adaptive). Improved clinical research design,
combined with advances in basic science, will to help to identify those ARI patients who are most ill and
require intervention; assess and develop effective interventions for SARI and CAP; and promote more
timely exchange of data and knowledge.
Priority research questions
5.1 Develop algorithms to identify high-risk patients and prognostic markers at an early stage of the
disease.
5.2 Validate specific protocols, including supportive-care interventions such as rehydration and
oxygen, to reduce the risk of severe outcomes. For instance, the use of a pulse oximeter for early
diagnosis and case management of hypoxemia warrants more study.
5.3 Develop and validate clinical management algorithms for optimizing SARI outcomes in resource-
limited settings, including use of a range of therapeutics and supportive or adjunct therapies.
5.4 Develop further evidence on oxygen therapy (protocols for use and benefits), to enable its
inclusion in the WHO list of essential medicines.
5.5 Promote research on oxygen delivery and dispensing devices that are better adapted to all
settings (including household and low-resource settings), particularly low-cost and easy-to-maintain
ventilatory support systems.
5.6 Determine feasible approaches to reducing risks of nosocomial transmission of viral respiratory
infections in health-care and household settings.
5.7 Compare the riskbenefit and cost-effectiveness of various therapeutic strategies (e.g. treatment
of mild cases, versus all cases, versus severe cases only).
5.8 Assess the conditions in the health-care systems to ensure the optimal implementation of
recommended changes.
5.9 Promote innovative clinical research design, and sharing of data and knowledge.
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References (Section 5)
50 Pavia AT. Viral infections of the lower respiratory tract: old viruses, new viruses, and the role of
diagnosis. Clinical Infectious Diseases, 2011, 52(Suppl 4):S284-289.
http://www.ncbi.nlm.nih.gov/pubmed/21460286
74 Voiriot G, Dury S, Parrot A et al. Nonsteroidal antiinflammatory drugs may affect the
presentation and course of community-acquired pneumonia. Chest, 2011, 139(2):387-394.
PM:20724739
75 Siempos II, Vardakas KZ, Kopterides P et al. Adjunctive therapies for community-acquired
pneumonia: a systematic review. The Journal of Antimicrobial Chemotherapy, 2008, 62(4):661-
668. PM:18641037
76 Rasmussen SA, Jamieson DJ. Influenza and pregnancy in the United States: before, during, and
after 2009 H1N1. Clinical obstetrics and gynecology, 2012, 55(2):487-497. PM:22510632
77 Panickar J, Lakhanpaul M, Lambert PC et al. Oral prednisolone for preschool children with acute
virus-induced wheezing. New England Journal of Medicine, 2009, 360(4):329-338. PM:19164186
78 Mytton OT, Rutter PD, Donaldson LJ. Influenza A(H1N1)pdm09 in England, 2009 to 2011: a
greater burden of severe illness in the year after the pandemic than in the pandemic year. Euro
Surveillance : European Communicable Disease Bulletin, 2012, 17(14). PM:22516004
79 McCullers JA. Preventing and treating secondary bacterial infections with antiviral agents.
Antiviral Therapy, 2011, 16(2):123-135. PM:21447860
80 Mandell LA, Wunderink RG, Anzueto A et al. Infectious Diseases Society of America/American
Thoracic Society consensus guidelines on the management of community-acquired pneumonia in
adults. Clinical Infectious Diseases, 2007, 44(Suppl 2):S27-S72. PM:17278083
81 Lee N, Ison MG. Diagnosis, management and outcomes of adults hospitalized with influenza.
Antiviral Therapy, 2012, 17(1 Pt B):143-157. PM:22311561
82 Kramarz P, Monnet D, Nicoll A et al. Use of oseltamivir in 12 European countries between 2002
and 2007 lack of association with the appearance of oseltamivir-resistant influenza A(H1N1)
viruses. Euro Surveillance : European Communicable Disease Bulletin, 2009, 14(5). PM:19215715
83 Greene SK, Shay DK, Yin R et al. Patterns in influenza antiviral medication use before and during
the 2009 H1N1 pandemic, Vaccine Safety Datalink Project, 2000-2010. Influenza and Other
Respiratory Viruses, 2012. PM:22687171
84 Garg S, Chaves SS, Perez A et al. Reduced influenza antiviral treatment among children and
adults hospitalized with laboratory-confirmed influenza infection in the year after the 2009
pandemic. Clinical Infectious Diseases, 2012, 55(3):e18-e21. PM:22543024
85 Ducharme FM, Lemire C, Noya FJ et al. Preemptive use of high-dose fluticasone for virus-induced
wheezing in young children. New England Journal of Medicine, 2009, 360(4):339-353.
PM:19164187
86 Corrales-Medina VF, Musher DM. Immunomodulatory agents in the treatment of community-
acquired pneumonia: a systematic review. The Journal of Infection, 2011, 63(3):187-199.
PM:21763343
87 Borders-Hemphill V, Mosholder A. U.S. utilization patterns of influenza antiviral medications
during the 2009 H1N1 influenza pandemic. Influenza and Other Respiratory Viruses, 2012.
PM:22681766
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Research needs for the Battle against Respiratory Viruses (BRaVe) 26 | P a g e
6. Optimizing public health strategies (88-102)
Vaccines remain at the heart of disease prevention and control strategies. However, among respiratory
viruses, only influenza has vaccines, and these are underused. Furthermore, the need for annual
immunization with current influenza vaccines, due to waning immunity and changing viral antigenicity,
highlights the importance of developing new vaccines with more durable and broader spectrum immune
responses. Development of vaccines against other respiratory viruses is a well-recognized research need,
and studies to develop vaccines for RSV and PIV have been ongoing for decades. Unfortunately, vaccine
development is a long process, and there are significant technical challenges with respiratory viruses.
Immune responses to infections by pathogens such as RSV, huMPV and PIV are incomplete, so
reinfections can occur. Consequently, effective vaccines will need to induce more effective protective
responses than natural infection. Both live-attenuated and subunit RSV vaccines are in development, but
it is uncertain whether vaccines will become available for RSV or other respiratory viruses within the next
510 years. Once available, maternal immunization, as shown for influenza vaccines, would offer the
possibility of protecting young infants.
Considering these potential limitations, further evidence is needed on effective implementation of public
health approaches, such as hand hygiene, cough etiquette and other population-based prevention
measures. Comparative scenarios weighting the cost-effectiveness of sets of measures to be
implemented would be an asset for policy makers, helping to transfer
knowledge into action.
Common misperceptions on RVIs are shared by health-care workers
and the general population. These misperceptions increase the
burden of RVI disease, because they are likely to delay or prevent
effective intervention. More high-quality data would provide policy
makers with strategies to help both groups comply with
recommended interventions and adhere to policies. Health-care
workers are especially important; they are a key group to mobilize
and educate the public, because they are generally trusted and seen
as reliable sources of information.
Another issue is that public health policies are increasingly
questioned by individuals in the media and general population. One
consequence is that adherence to recommended interventions may,
in certain situations, be very low in the population. In many countries,
recent decades have seen a switch from a paternalistic model, in which governmental guidance was
generally accepted and followed, to one based on individual choice and freedom of action as personal
rights.
Most common
misperceptions:
There is no effective
treatment for viruses;
Viral infections are not that
severe;
Vaccines are the only
approach possible for viral
infections;
Emerging viruses are most
likely to cause deadly
pandemics.
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Research needs for the Battle against Respiratory Viruses (BRaVe) 27 | P a g e
More research is needed on strategies to prevent and control RVIs, and on the timely and effective
integration of innovation and advances in science in decision-making and public health practices.
Particular attention should be given to communicating to different stakeholders, especially health-care
workers, who are pivotal in implementing change in health-care systems. Having better data on current
knowledge and practices will allow more refined strategies and improved local adaptation and
implementation. The link between evidence and practice should be emphasized.
Priority research questions
6.1 Compile evidence to support the development of relevant public health strategies preventive
and responsive; individual and community-based to mitigate the impact of respiratory viral infections.
6.2 Survey the landscape of vaccines for non-influenza respiratory viruses, and promote efforts to
develop effective vaccines for key target groups.
6.3 Study knowledge, attitudes and practices of:
HCWs in relation to common and severe respiratory diseases in different settings;
the general public on respiratory viral infections, to increase adherence to public health
measures.
6.4 Assess the impact of various communication strategies to improve the management of
respiratory infections.
6.5 Develop mathematical models to guide decisions about the most effective combination of
measures to mitigate the impact of viral respiratory infections.
6.6 Assess and compare current decision-making processes related to respiratory viral infections in
different settings, health-care systems and risk groups.
References (Section 6)
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demographic class. Epidemics, 2011, 3(1):19-31. PM:21339828
90 Cohen AL, Hyde TB, Verani J et al. Integrating pneumonia prevention and treatment
interventions with immunization services in resource-poor countries. Bulletin of the World
Health Organization, 2012, 90(4):289-294. PM:22511825
91 Hollingsworth TD, Klinkenberg D, Heesterbeek H et al. Mitigation strategies for pandemic
influenza A: balancing conflicting policy objectives. PLoS Computational Biology, 2011,
7(2):e1001076. PM:21347316
92 Larson EL, Ferng YH, Wong-McLoughlin J et al. Impact of non-pharmaceutical interventions on
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93 Lau JT, Griffiths S, Choi KC et al. Avoidance behaviors and negative psychological responses in the
general population in the initial stage of the H1N1 pandemic in Hong Kong. BMC Infectious
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96 Poletti P, Ajelli M, Merler S. The effect of risk perception on the 2009 H1N1 pandemic influenza
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98 Ungchusak K, Sawanpanyalert P, Hanchoworakul W et al. Lessons learned from influenza
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99 van der Weerd W, Timmermans DR, Beaujean DJ et al. Monitoring the level of government trust,
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100 World Health Organization. Stream 3, Minimizing Impact: Minimizing the impact of pandemic,
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101 World Health Organization. Clinical management of influenza and other acute respiratory illness
in resource-limited settings: learning from the influenza pandemic (H1N1) 2009. Geneva, WHO,
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102 Xue Y, Kristiansen IS, de Blasio BF. Modeling the cost of influenza: the impact of missing costs of
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