technical update on prevention of hiv transmission in health care … transmission in... · hiv...

HIV Technical BriefsHIV Technical BriefsHIV Technical BriefsHIV Technical Briefs For use by WHO staff and consultants

1

Prevention of HIV Transmission in Health Care Settings

Updated on May 18 2007

Technical elements The essential elements of the prevention of HIV transmission in the Health Care Settings are complementary and should be integrated in a comprehensive health sector response; they include:

Primary prevention procedures:

• Blood Safety: aims to strengthen capacities of blood transfusion services to ensure that all blood units are collected from healthy, voluntary, unpaid donors. After assessing donor's suitability for blood donation, blood units are screened for transfusion- transmissible infections, including HIV. Only non-reactive units are released for clinical use . The programme also aims to reduce unnecessary transfusions, to prevent HIV transmission through unsafe blood, to make safe blood available in management of complicated pregnancies, severe anaemia, malaria, AIDS patients on ART, accidents and trauma, cancer treatment and haematological conditions.

• Prevention of unsafe injections and the Safe Injection Global Network (SIGN): a unique network of stakeholders promoting injection safety and providing normative guidance related to injection safety and infection prevention.

• Emergency and Essential Surgical Care: aims to strengthen capacities at primary health care facilities for emergency and surgical interventions in trauma, pregnancy-related complications, surgical conditions, male circumcision and infections (including HIV);implement surgical and anaesthetic techniques to limit the need for blood transfusion and improve standard precautions, sterilization of equipment, surgical waste disposal.

• Standard Precautions: are meant to minimize the spread of infection associated with health care and to avoid direct and indirect contact with blood, body fluids, secretions and non-intact skin. They are the basic infection control precautions in health care and involve hand hygiene, use of personal protective equipment to prevent exposures, safe disposal of sharps and waste, and safe cleaning and disinfection of the environment and equipments.

• Occupational Health: aim to identify, eliminate and control exposure to hazards in the workplace. Preventing needlestick injuries and occupational exposure to blood includes eliminating unnecessary injections and sharps use, applying Standard Precautions procedures (such as prohibiting recapping of needles and ensuring safety disposal immediately after use of the sharp)

• Safe waste disposal: is key to prevent the transmission of bloodborne pathogens. Sharps waste, although produced in small quantities, is highly infectious. Poorly managed, contaminated needles and syringes represent a particular threat to the staff and patients but also to the community at large when waste end up in uncontrolled waste areas and dump site at the health care facility where they are scavenged and reused.

Secondary prevention measures in health care settings: are applicable when primary prevention has failed, when a health care workers or patient has been, accidentally or through unsafe procedures, exposed to the risk of HIV transmission

• Post exposure prophylaxis for HIV refers to a set of comprehensive services to prevent infection to develop in the exposed person. These services include first aid care; counselling and risk assessment; HIV testing -based on informed consent- and, depending on the risk assessment, the provision of short term (28 days) antiretroviral drugs, with follow up and support.


2

Facts & figures: Global burden of diseases.

WHO has estimated that about 5% of new HIV infections in developing and transitional countries may be attributable to unsafe health care injections, including unsafe blood and occupational exposures. This global estimate varies according to regions, with higher percentages for Asia compared to other parts of the world. It is important to point out that for a number of reasons, there is substantial uncertainty around this estimate and more research and data are needed to obtain a reliable picture of the situation. In 2000, WHO estimated that contaminated injections caused annually 21 million HBV infections, two million of HCV infections and 260 000 HIV infections These infections, led to 49 000, 24 000, and 210 000 deaths, respectively. 40% of the global burden of hepatitis B and C among health workers is attributable to occupational exposure. During a transfusion of blood infected with HIV, the recipient is exposed to more infectious material than by any other means of acquiring HIV infection. The transfusion of unsafe blood and blood products therefore poses an exceptionally high risk of transmission of HIV (95–100%) compared to other common routes of HIV exposure: for example, 11–32% for perinatal HIV transmission and 0.1%–10% for sexual contact Around 2.7 million units of blood were collected in 40 sub-Saharan countries in 2004; 88.5% of these were not tested for HIV in a quality-assured manner. With high numbers of obstetric complications, malaria, helminth infections, malnutrition and sickle cell disease, life-threatening anaemia occurs more frequently in Africa than in most parts of the world. African children are particularly vulnerable. ( in 2006, only 40 countries in the world have achieved 100% voluntary blood donation ) Each year at least 16 billion injections are administered in developing and transitional countries. The vast majority, around 95%, are given in curative care. Immunization accounts for around 3% of all injections, with the remaining include uses such as contraceptives. In a study (Bull WHO 1997;75(2):133-40), the annual occupational risk of HIV transmission was estimated at 0.27% for health workers (Mwanza Tanzania). Among surgeons, the risk was 0.7% (i.e more than twice as high) if no special protective measures were taken. Health service providers may become infected with HIV through needle stick injuries and injuries during surgery. There is a need for a comprehensive AIDS management package that would offer specific preventive and psychological training in care of HIV patients and provide requisite funds and resources to surgeons and care givers of HIV- infected patients. Poor caring practices by HIV-infected medical staff may also carry a risk of infection for the patient. And when injecting and other equipment is poorly sterilized, HIV may be carried from an HIV-infected to an uninfected patient in the health care settings. There is a need to improve the use of standard infection control measures and to educate all categories of healthcare personnel in order to allay the fears and to prevent discrimination that could militate against effective management of HIV/AIDS patients


3

Operational Considerations

In supporting countries, efforts should focus on advocacy and policy implementation, capacity building, monitoring and quality assurance. Aiming at strengthening the health sector safety, the prevention efforts should not be limited to HIV transmission but include all preventable blood borne pathogens. Prevention measures of transmission in the health care settings are implemented for the sake of services providers and patients. The key actions to consider in implementing interventions for the prevention of HIV transmission in the health care settings at country level should include:

• Advocacy: promote of the ZERO tolerance policy on HIV/AIDS and other blood borne diseases transmission in health care settings, this, to the benefit of health care workers and patients;

• Evaluation and evidence based research: collect data, case study and operational research to inform policies;

• Policy guidance: develop and update national policies and legislation with regard to HIV transmission in the health settings; informing politicians, decision-makers health institution about the urgent need to implement safety measures and prevention of HIV transmission through specific interventions; disseminating evidence and experience. Authorities should also review safety and compensation plans, safety enforcement practices and provision of health services to create an environment in which prevention programmes are systematically implemented;

• Tools and guidelines: provide or adopting adaptated tools; integrating guidelines in national strategic plans and curricula.

• Services: include the provision of commodities, protection masks, gowns, gloves; single use blades needles and syringes; syringes with reuse prevention features; provision of safe blood and blood products; provision and disposal of sharps and medical waste containers; immunization of healthcare workers against the hepatitis B virus; access to PEP services and provision of PEP services including HIV testing and counselling,

• Capacity building: develop pre and in service training curricula; ongoing information and monitoring of health workers, including but not limited to all health and social service professionals who come into contact with blood and body fluids products.

• Monitoring and evaluation: select indicators for national HIV/AIDS programmes to assist in the monitoring of coverage, quality and effectiveness of programmes; risk assessment and evaluation of the burden of the disease; surveillance, reporting and evaluation of occupational exposure to bloodborne pathogens in the workplace.

• Quality assurance: monitor the quality of services and products is a paramount and in linkage with external laboratories, warrants safe procedures .


4

Services and interventions

Key and specific interventions within the context of a comprehensive approach

Type of intervention

Key activities to be implemented

Blood transfusion safety

• Strengthen capacity of countries to establish safe blood transfusion services.

• Promote and coordinate the development of strategies, tools and guidelines to ensure universal access to safe blood and blood products.

• Increase voluntary unpaid blood donation and reduction in family/replacement and paid donation, by developing blood donor programmes and providing training to blood donor programme managers.

• Strengthen capacity of countries on quality-assured screening of all donated blood for HIV.

• Support countries in developing systems for reducing the need for transfusion and reducing unnecessary transfusions.

• Develop HIV counseling guidelines and building capacity in countries to provide HIV counseling to blood donors.

• Maintain safe blood transfusion systems in emergency situations.

• Ensure safe disposal of needles, and blood collection bags and safe waste management in blood transfusion services.

Prevention of unsafe injections

• Promote and coordinate the development of strategies, tools and guidelines to ensure rational and safe use of injections.

• Develop culturally adapted communication strategies targeting health care workers and the community in order to reduce injections overuse and create consumer demand for safety devices.

• Disseminate information and organize the SIGN global meetings and working groups.

Emergency and Essential Surgical Care

• Support strengthening capacities at primary health care facilities through the Global Initiative for Emergency and Essential Surgical Care

• Incorporate WHO Integrated Management for Emergency and Essential Surgical Care tools in country training programs towards a comprehensive approach for strengthening capacities at primary health care facilities

• Implementing measures for the prevention of HIV transmission, surgical and anaesthetic techniques to limit the need for blood transfusion; standard precautions; sterilization of equipment; waste disposal;

Standard precautions

• Respect hand hygiene before and after any patient contact and after contact with contaminated items, whether or not gloves are worn.

• Wear personal protective equipment based on risk assessment and to avoid contact with blood, body fluids, excretions, and secretions.

• Ensure appropriate handling of patient-care equipment and


5

soiled linen

• Prevent needlestick/sharp injuries.

Occupational Health

• Immunize workers against hepatitis B,

• Form health and safety committees in the health care workplace to identify hazards and recommend controls,

• Provide occupational health services.

Waste disposal • Set, validate and monitor norms and standards through developing:

o Ethical and evidence based policies o Guidelines on waste management o Tools and guidelines for disease control and risk

management

• Stimulate the research, development and testing of new technologies

• Provide support for sustainable capacity building

HIV Post Exposure Prophylaxis for occupational exposure

� Provide and promote PEP guidelines, in occupational and non occupational settings, as an integral part of prevention treatment and care services.

� Integrate PEP in national strategic and operational plans with a focus on training, service provision, procurement of ARVs and commodities, communication, monitoring and evaluation;

� Operationalize PEP in providing the comprehensive set of services: first AID care, counseling for PEP; HIV testing and counseling; risk evaluation; provision of ART; follow up and support

Key messages

Key messages


Reducing transmission of HIV infection through unsafe blood, through

• Voluntary unpaid blood donation: the collection of blood only from the safest possible regular, voluntary unpaid blood donors from low-risk populations and stringent criteria for assessing the suitability of blood donors.

• Universal testing of donated blood in a quality-assured manner: the quality-assured screening of all donated blood for, at minimum, HIV, hepatitis B, hepatitis C and syphilis. , based on standard operational procedures and the participation of laboratories inan External Quality Assessment Scheme (EQAS)

• Reduction in unnecessary transfusions: by reducing the need for transfusion; safe and rational blood utilization and the use of alternatives to transfusion, wherever possible.

Injection safety

Prevention of Injection overuse and safe injection practices need to be supported by:

• specific strategies

• continuous availability of safe, good quality injection devices and sharps containers


6

• appropriate , ongoing training and monitoring of all injection providers


• Skills building at primary health care facilities in safety of surgical and anaesthesia procedures and equipment

• Use of appropriate surgical and aesthesia techniques to limit the use of blood transfusion, standard precautions during emergency and surgical procedures.

• Availability of WHO Best Practice Protocols for Clinical Procedures Safety (hand washing, prevention of HIV transmission, sterilization of equipment, emergency equipment list)

Standard Precautions

• Promotion of an institutional safety climate helps to improve conformity with recommended measures and thus subsequent risk reduction. Provision of adequate staff and supplies, together with leadership and education of health workers, patients, and visitors, are critical for an enhanced safety climate in health-care settings.

• Standard Precautions should be the minimum level of precautions used when providing care for all patients.

• Risk assessment is critical. Assess all health-care activities to determine the precautions that are indicated.

Occupational Health

• Healthcare workers are workers and the healthcare workplace is a complex and hazardous environment.

• Preventing needlestick injuries will prevent 90% of occupational transmissions of HIV. Use of safer needle devices and needle less IV systems, eliminating recapping of needles, and placing needles and sharps into sharps containers immediately after use are the most important ways to reduce exposure to injuries,

• Document and analyze workplace exposures to identify the need for changes in products and procedures, best practices and policies for prevention.

Waste disposal � Promoting environmentally sound management policies for health-care waste is the basis of efficient prevention of health risks associated with exposure to health care waste of the health workers and the public


� PEP should be initiated as soon as possible, within the first few hours -and no later than 72 hours- after exposure to HIV potentially infected blood or body fluids;

� PEP is not be prescribed to HIV infected persons; � HIV testing is strongly recommended and could be done

after initiation of PEP; testing could be repeated after 3 and 6 months:

� The WHO recommended regimen is based on 2 NRTIs unless HIV resistance may be suspected: in this case, the addition of a PI could then be recommended;

� Adherence is critical: ARVs for PEP should be taken for 28 days, continuously;

� In addition to risk evaluation and counseling, psycho-social support is needed;

� Any occupational exposure to HIV should lead to evaluation and when relevant, strengthening of safety and working conditions.


7

Common challenges The main challenges are to:

• Provide the necessary human and financial- resources- to fund and implement the programmes;

• Disseminate and implement standard operational procedures;

• Provide regular supplies of examination and surgical gloves, sterile needles, sterilization equipment, ARVs, safe blood and blood products and testing material and safe waste containers;

• Protect, treat, train and retain overburdened staff.

WHO contribution at global level WHO is mandated to:

•••• Provide technical advice and guidance, based on scientific evidence; •••• Support countries in planning, managing and implementing programme •••• Develop evidence-based policies, standards and programming tools to support country

level implementation; •••• Support regional and national planning and capacity building; •••• Generate and disseminate strategic information; •••• Support the strengthening of health systems; •••• Provide monitoring and evaluation tools and indicators. WHO contribution at country level : • Advocate and assist ministries of health in implementing policies and strengthening

coordination .

• Coordinate efforts to ensure that all relevant government ministries/departments, technical agencies, academic institutions, private sector, donor organizations and the UN agencies are involved;

• Galvanize political will and commitment of national governments and key stakeholders to accelerate scale up efforts to achieve the goal of elimination of HIV infection transmission in Health Care settings;

• Assist national governments in mobilization and effective allocation of resources to support scale up efforts;

• Support procurement and supply management of commodities, protective equipment, training tools, and ARVs for PEP.

• Provide technical support for the development, adaptation and implementation of HIV-related blood safety, injection safety, standard precaution, safety of clinical and surgical procedures, safe health care waste management, occupational health, post exposure prophylaxis for HIV policies, guidelines and tools;

• Support national processes of strategic planning around blood safety, injection safety, standard precaution, surgical safety (procedures and equipment), occupational health, post exposure prophylaxis for HIV, safe health care waste management;

• Advocate and support human capacity development related to prevention of HIV in Health Care Settings

• Promote safe water, sanitation and hygiene in health care settings to control the development of opportunistic diseases in HIV/AIDS patients.

• Provide technical assistance on strategic information, including monitoring and evaluation, operational research, and documentation and dissemination of experiences


8

Key Resources

Key documents, tools , links and references


• http://www.who.int/bloodsafety/

• http://www.who.int/worldblooddonorday/en/

• Aide-Memoir: Blood Safety

• Aide-Memoir: The Clinical Use of Blood

• Recommendations: Developing a National Policy and Guidelines on the Clinical Use of Blood

• The Clinical Use of Blood: Handbook

• The Clinical Use of Blood in General Medicine, Obstetrics, Paediatrics, Surgery and Anaesthesia, Trauma and Burns: Module

• Distance Learning programmes for safe blood and blood products

• Quality management of blood transfusion services

• Recruiting and Retaining Voluntary Non-Remunerated Blood Donors

• Draft WHO Recommendations on Screening of Donated Blood for Transfusion Transmissible Infections in Blood

http://www.who.int/bloodsafety/global_database/

Injection safety

• Safety of injections. World Health Organization, Geneva. WHO (10

September), 2003.

http:/ w ww.who.int/injection_safety/sign/en/

• Guiding principles to ensure injection device security. World Health Organization,

Geneva.

• UNICEF-UNFPA. Safety of injections. Joint statement on the use of auto-disable syringes in immunization services. WHO/V&B99.25. Available at:www.who.int/vaccines-documents/DocsPDF99/www9948.pdf

• Managing a national Programme on Injection safety: http://www.who.int/injection_safety/toolbox/en/ManagingInjectionSafety.pdf

• Guiding principles to ensure availability of injection equipment http://www.who.int/injection_safety/WHOGuidPrinciplesInjEquipFinal.pdf

• Injection safety Toolbox: http://www.who.int/injection_safety/sign/en/


• Best Practice Protocols on Clinical Procedures Safety www.who.int/surgery/imeesc

• Waste Disposal in Clinical Procedures at Resource Limited Health Care Facility www.who.int/surgery/imeesc

• WHO Generic Essential Emergency Equipment List in WHO Integrated Mangement for Emergency and Essential Surgical Care toolkit

www.who.int/surgery/activities

• WHO manual Surgical Care at the District Hospital: Male circumcision www.who.int/surgery

Standard Precautions

• Prevention of hospital-acquired infections, 2nd edition. 2002. A practical guide. at http://www.who.int/csr/resources/publications/csrpublications/en/index7.html

• EPR Infection control publications at http://www.who.int/csr/resources/publications/csrpublications/en/index7.html

• "Clean Care is Safer Care":


9

http://www.who.int/gpsc/tools/en

• WHO Aide –memoir: Standard Infection control precautions in health care. WHO, available at: http://www.who.int/csr/resources/publications/standardprecautions/en/index.html

• WHO Guidelines on Hand Hygiene in Health Care (Advanced Draft) at http://www.who.int/patientsafety/information_centre/ghhad_download/en/index.html

• "Practical guidelines for infection control in health care facilities" WPRO/SEARO, 2004 at: http://www.wpro.who.int/publications/PUB_9290222387.htm

Occupational Health

• Joint ILO/WHO guidelines on health services and HIV/AIDS: number 32-53 and

Fact Sheet No. 4, Hierarchy of controls applied to risk of blood-borne pathogen

exposure

http://www.who.int/hiv/pub/prev_care/healthservices/en/index.html

• Protecting healthcare workers – preventing needlestick injuries tool kit in English

http://www.who.int/occupational_health/topics/needinjuries/en/index.html

and in Spanish at : http://ww.who.int/occupational_health/activities/pnitoolkit/es/index.html

• WHO Aide-memoir: Healthcare worker safety

http://www.who.int/injection_safety/toolbox/docs/AM_HCW_Safety.pdf

• Sharps injuries: Assessing the burden of disease from sharps injuries to health-care

workers at national and local level

http://www.who.int/quantifying_ehimpacts/global/globsharpinjuries/en/index.html

Waste disposal

• Management of solid health-care waste at primary health-care centres: A decision-making guide

http://www.who.int/water_sanitation_health/medicalwaste/hcwdmguide/en/index.html

• Management of waste from injection activities at district level http://www.who.int/water_sanitation_health/medicalwaste/mwinjections/en/index.html

• Safe healthcare waste management: Policy paper http://www.healthcarewaste.org/en/160_hcw_policy.html http://www.who.int/water_sanitation_health http://www.healthcarewaste.org


Post Exposure Prophylaxis for HIV:

• Joint WHO-ILO Guidelines and Policies for the Use of Occupational and Non-Occupational Post Exposure Prophylaxis (PEP) to Human Immunodeficiency Virus (HIV)(to be published)

• Joint ILO/WHO guidelines on health services and HIV/AIDS: Fact Sheet No. 10.

Summary outline for the management of occupational exposure to blood-borne

pathogen, pp. 75-76. ILO: 2005 Geneva. http://www.who.int/hiv/pub/prev_care/who_ilo_guidelines.pdf

Contacts


10

WHO HQ Programme Contact Address

HIV/AIDS/ATC Prevention of HIV in Health care Settings. PEP-

Micheline Diepart [email protected] +41 7915486

EHT/Blood Safety Neelam Dhingra- Kumar [email protected],

EHT/SIGN Selma Khamassi [email protected]

Standard Precautions Carmem Pessoa-Da-Silva. Gerald Dziekan

[email protected]; [email protected]

EHT/CPR Emergency and Essential Surgical Care

Meena Cherian, [email protected]

Occupational health Gerry Eijkemans Susan Wilburn

[email protected] [email protected]

Waste management Yves Chartier [email protected]

AFRO HIV/AIDS/ATC Prevention of HIV in Health care Settings. PEP

Dr R Vaz, Regiional Adviser, HIV/AIDS.

vazr@@afro.who.int

EHT/Blood Safety Dr Jean Baptiste Tapko Regional Adviser Blood Safety (BLS) Division of Health Systems and Services Development (DSD)

Tel.: 39250 (GPN) Fax: (GPN) e-mail: [email protected]

EHT/SIGN Dr Jean-Baptiste Tapko [email protected]

Standard Precautions Dr Adamou Yada [email protected]


Dr Jean-Bosco Ndihokubwayo, RA-CLT/Essential Health Technologies

Ndihokubwayo, Dr. Jean Bosco - bzv

Occupational health Thebe Pule [email protected]

Waste management Ahmed Nejjar [email protected]

AMRO HIV/AIDS/ATC Prevention of HIV in Health care Settings. PEP-

Dr Bilali Camara, REgional Adviser HIV/AIDS/STIs

[email protected]

EHT/Blood Safety Dr Jose Ramiro Cruz RA/BLS

Tel: 5200-3230 (GPN) [email protected]


11

EHT/SIGN Mr Antonio Hernandez [email protected]

Standard Precautions Dr Marlo Libel [email protected]


Dr. Jose Luis Di Fabio, Area Manager,

+1 202 974 3788 [email protected]

Occupational health Maritza Tennassee [email protected]

Waste management Luz Maritza Tennassee Diego Diaz


EMRO HIV/AIDS/ATC Prevention of HIV in Health care Settings. PEP-

Dr Gabriele Riednder, Regional Adviser, HIV/AIDS/STIs.

[email protected]

EHT/Blood Safety Dr Nabila Metwalli Regional Adviser Blood Safety and Laboratory

Tel.: 65314 (GPN) Fax: 65416 (GPN) e-mail: [email protected]

EHT/SIGN Dr Irtaza Chaudry [email protected]

Standard Precautions Dr Hassan El Mahdi EL BUSHRA

[email protected]


Dr Nabila Metwali Regional Advisor, Essential Health Technologies

Tel: +202 2765314 Fax: +202 2765416 Cell Phone: +2012 2177909 e-mail: [email protected] www.emro.who.int

Occupational health Said Arnaout [email protected]

Waste management Houssain Abouzaid Raki Zghondi


EURO HIV/AIDS/ATC Prevention of HIV in Health care Settings. PEP-

Dr Srdan Matic, Regional Adviser, HIV/AIDS

[email protected]

EHT/Blood Safety Dr Valentina Hafner STP/BTS

Tel: 5300 1255 (GPN) Fax: 5300 1851 (GPN) e-mail: [email protected]

EHT/SIGN Dr Valentina Hafner [email protected]

Standard Precautions Dr Nedret Emiglou [email protected]


Dr Enrico Davioli EMS - Emergency Medical Services Programme

tel: +34 93 2418270 e-mail: [email protected] web-site: www.euro.who.int/emergservices

Occupational health Rokho Kim [email protected]

Waste management Roger Aertgeerts [email protected]


12

Eric Laurent [email protected]

SEARO HIV/AIDS/ATC Prevention of HIV in Health care Settings. PEP-

DrYing Ru Lo, Regional Adviser, HIV,

[email protected]

EHT/Blood Safety Dr Rajesh Bhatia Regional Adviser Blood Safety & Clinical Technology & Regional Focal Point for Zoonotic Infections

WHO House Indraprastha Estate Ring Road New Delhi 110002 Phone: +91-11-23309504 e mail:[email protected]

EHT/SIGN No focal point identified

Standard Precautions Dr..Khanchit Limpakarnjanarat

[email protected]


DR. SULTANA KHANUM Director Health Sytems Development (HSD)

Tele : +91(0)11 23370804 Direct : +91(0)1123309 325 Internal : 26341/ 26325 Fax : +91(0)11 23370252 Mobile Number : 9818348926 [email protected]

Occupational health Habibullah Saiyed [email protected]

Waste management Alexander Von Hildebrand [email protected]

WPRO HIV/AIDS/ATC Prevention of HIV in Health care Settings. PEP-

Dr. Massimo Ghidhinelli, HIV/AIDS Regional Adviser,

[email protected]

EHT/Blood Safety Mr Yu Junping Health Technology,

Tel: + 632 528 9848 Fax: +632 521 1036 Email: [email protected]

EHT/SIGN Dr Yu Jumping [email protected]

Standard Precautions Dr Takeshi Kasai [email protected]


Dr Yu, Dr Junping - wpro [email protected]

Occupational health Hisashi Ogawa [email protected]

Waste management Terrence Thompson [email protected]

technical update on prevention of hiv transmission in health care … transmission in... · hiv...

Documents