bob meyer's hiv/aids reporting refresher course

8/6/2019 Bob Meyer's HIV/AIDS Reporting Refresher Course

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Refresher Course

For

J2J Fellows

Presenter: Bob Meyers, NPF & J2J


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Why are we doing this?

To make sure that all journalists

are on a level playing field in their

knowledge of HIV/AIDS


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We will look at

HIV/AIDS in threeways. As a

Medical/Scientific Issue

Public Health Issue

Medicine & Public Health compared forthe benefit of journalists


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Some basic definitions

HIV Human Immunodeficiency Virus

AIDS Acquired Immune Deficiency Syndrome

Medicine a focus on the individual

Public health a focus on populations

Incidence the number of new cases arising in a given population

in a given time

Prevalence the proportion of people with HIV at a specific point

in time; expressed as a %.


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HIV/AIDS

As A

Medical/Scientific

Issue


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What Does AIDS DoIn the Body?

AIDS is a disease of the immune

system The immune system is a networkof

cells and organs throughout the body

HIV destroys the immune system.


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What Does AIDS DoIn the Body?

HIV primarily attacks one type of cell that is

crucial to the immune system: The CD4 T-

helper cell After exposure, the body cannot fight off

infections, and so it succumbs to opportunistic

infections such as TB, pneumonia, etc., which

is why AIDS is a syndrome.


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AIDS is caused by HIV,

the Human ImmunodeficiencyVirus

Courtesy of Anthony S. Fauci, National Institute of Allergy and Infectious Diseases


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In many ways,

HIV acts like most other

virusesAnd the immune system treats it

like any other virus


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Video from Howard Hughes Medic
http://www.hhmi.org/biointeractive/disease/hiv_life_cycle.htmlhttp://www.hhmi.org/biointeractive/disease/hiv_life_cycle.html


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But in a few crucial ways

HIV differs from other viruses

When the immune system responds after

HIV attacks it, HIV turns the immune systemcounter-attack to its own advantage

This allows HIV to persist in the body for

years and finally destroy the immune system


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The immune system is a

networkof organs and cells

Mucosal barriers:Vagina, rectum,mouth.

Lymphatic vessels:the immunesystemsbloodstream

Lymph nodes &GALT: cleansingcenters

Thymus, spleen,

bone marrow etc.Images from The National Cancer Institute, http://newscenter.cancer.gov/sciencebehind/immune/immune00.htm


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15Slide courtesy of Anthony S. Fauci, National Institute of Allergy and Infectious Diseases


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The immune system is complex

and interactive Immune-system cells detect invading viruses and

bacteria

Immune system cells mobilize each other by: Direct cell-to-cell contact

Excreting messenger molecules such as cytokines

Immune system cells destroy invading viruses by: Excreting antibodies that snare free-floating virus

Killing the bodys own cells that have been infected

Excreting molecules such as chemokines that interferewith viral replication


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The CD4+ T-helper Cell

CD4+ means that the cell displays(expresses) a molecule on its surface calledCD4. HIV attaches to this molecule and, like alock and key, uses it to enter the cell.

Helper means that this cell helps other partsof the immune system do their job. If the immunesystem is an orchestra, this cell is the conductor.

T is short for Thymus-derived and is a type ofimmune cell. There are other T-cells, such askiller T-cells.


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2-3 Days

New virus

assembly

HIV replicates in CD4 cells. Amount o

virus produced determines disease course

Slide (slightly adapted) courtesy of Bruce D. Walker, Massachusetts General Hospital, Harvard Medical School, Partners AIDS Research Center


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New research suggests that

This time frame may be a matter of

HOURS, not days

Which could be one factor in failure of recent

vaccine trials

Inserted by Bob Meyers, 2008


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Typical Course of HIV infection

Graph courtesy of Anthony S. Fauci, National Institute of Allergy and Infectious Diseases


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Relationship Between CD4 and

Plasma HIV viral load

AIDS is like a trainheading toward acrash

Viral load indicatesthe speed of the train

CD4 count indicatesthe distance to thecrash


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CD4 Count

in Phases of HIV Infection

5-14 days

Incubation

CD4

cellco

unt

1-4 mo. 4-10 years 1-2 years

PrimaryPresymptomatic

AIDS

Slide (slightly adapted) courtesy of Timothy Schacker, University of Minnesota


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The level of HIV in the blood

predicts disease course

Amoun

tof

VirusinB

lood

One year

Rapid Progression

Slow Progression

Slide (slightly adapted) courtesy of Bruce D. Walker, Massachusetts General Hospital, Harvard Medical School, Partners AIDS Research Center


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Immune system detects HIV

and sounds the alarm

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At the cellular level

Macrophages and dendritic cells eat HIV Macrophage comes from macro for big and phage for eat.

So macrophages are Big Eaters, or scavenger cells

These scavenger cells cut up the virus into fragmentscalled antigens or epitopes

They present these viral fragments to other cells,including CD4+ T-cells Each CD4+ T-cell can recognize only one epitope

When it meets its particular epitope, the CD4 T-cell clones itselfinto an army of identical cells

These activated cells stimulate other immune-systemcells, such as B-cells, which make antibodies, and killerT-cells, which kill infected cells


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HIV prefers to infect

activatedCD4 T-cells

93-99% of HIV infects activated CD4

cells, which are HIVs favorite food

HIV occasionally infects unactivated or

resting CD4 cells, where for years it can

hide from the immune system

By activating CD4 cells to mobilize a

counterattack, the immune system is

actually feeding HIV


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Function of the CD4 T Cell

after infection

Resting CD4Cell

Activated CD4Cell

Macrophage, Dendritic Cell,or other Antigen Presenting Cell

Promote B-cell Antibody

Response (also calledHumoral response)

Promote Killer T-cells(also called CTL

short for CytotoxicT-Lymphocyte)

Secrete Chemokines

RantesMip 1 alpha

Mip 1 Slide (slightly adapted) courtesy of Timothy Schacker, University of Minnesota


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(Pause)

Why are we spending

so much time on thisscience stuff?


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How antibodies work

Antibodies work bybinding to particularfragments of HIV as

the virus floats in theblood or lymph.

These fragments arecalled epitopes.

When the antibodybinds to the epitope, itneutralizes the virus,rendering it harmless.

Graphic (slightly adapted) courtesy of Bruce D. Walker, Massachusetts General Hospital, Harvard Medical School, Partners AIDS Research Center


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New virus

assembly

Antibodies try to snare HIV

B cell

Slide (slightly adapted) courtesy of Bruce D. Walker, Massachusetts General Hospital,

Harvard Medical School, Partners AIDS Research Center


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But HIV eludes antibodies

HIV is sheathed in anenvelope The envelope is the most

mutable part of HIV, so HIVkeeps changing its coat,

making it impossible forantibodies to bind.

HIV uses part of theenvelope to enter cells But these critical parts are

cloaked with carbohydratemolecules. Antibodiesrarely bind effectively tocarbohydrates.

Image from The National Cancer Institute, http://newscenter.cancer.gov/sciencebehind/immune/immune00.htm


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Killer T-cells

are big guns in viral infections

Antibodies snare free-floating virus

But viruses infiltrate cells

They turn the cells into factories that churn out

thousands of copies of themselves

Inside the cells, they are protected from antibodies

HIV also mutates to escape the antibodies

Killer T-cells kill cells that HIV has infected


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This is one scientificreason that HIV is so

difficult to stop once it isin the body

and why AIDS is so difficult to

cure.Look

HIV replicates mainly in lymph


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HIV replicates mainly in lymph

tissue, the immune-system

stronghold

Images from The National Cancer Institute, http://newscenter.cancer.gov/sciencebehind/immune/immune00.htm


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Site of HIV Production and

Storage

Photos and slide (slightly adapted) courtesy of Timothy Schacker, University of Minnesota

Lymph tissue with HIV stained

to look bright. Stars are cells

producing HIV.

Close up of several cells in

lymph tissue producing HIV


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HIV in the lymph nodes

The lymph nodes normally trap viruses in the lymphoidgerminal centers and cleanse the viruses from the body.

The lymph nodes trap HIV, but doing so activates CD4 T-cells. Therefore, lymph nodes provide food for HIV:

activated CD4+ T-cells. HIV prefers to be in the very place where the immune

system kills most other viruses. HIV sets up camp in theimmune systems stronghold.

But: The fight between HIV and the immune system is

balanced at a standoff for many years


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HIV destroys the lymph nodes

HIV causes persistent lymph-node swelling, or

lymphadenopathy, one of the signs of HIV

infection.

Chronic, long-lasting activation of the immunesystem, combined with HIVs disruption of the

normal immune regulation, causes physical

destruction of the lymph nodes.

The lymph nodes can no longer trap and destroy

HIV. The delicate balance tips in favor of HIV.

L h i i HIV i


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Lymph tissue in HIV-negative

and HIV-positive people

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HIV-negative

personUpper left-hand corner: round

germinal center surrounded

by healthy mantle

HIV-positive

for 5 years, noARV treatment

All geographical

features destroyedno

discernible germinal centers

Photos and information courtesy of Timothy Schacker, University of Minnesota


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The consequences of HIV

infection As HIV slowly wins the battle, the immune system

can no longer repel some infections.

These are called opportunistic infections (OIs for short)

because they take the opportunity given to them by the

weakened immune system.

These other infections are what kills people. HIV

itself does not (though it can cause dementia.)

A ti t i l d (ARV )


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Antiretroviral drugs (ARVs)

attack HIV itself They stop HIV from replicating, but they do not

eradicate HIV from the body

They allow the immune system to recover Not full immune reconstitution. Lymphoid tissue often

retains signs of damage; CD4 cells often dont rise topre-HIV levels.

But usually enough immune recovery to fight off mostinfections.

Therefore, ARVs take the place of drugs toprevent or treat most OIs

But antiretroviral drugs are expensive


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Lymph nodes in HIV-negative


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Lymph nodes in HIV-negative,

HIV-positive, and ARV-treated

patients

HIV-negative

person

Upper left-hand corner:

Round germinal center

surrounded by healthy mantle

HIV-positive

for 5 years, noARV treatment

All geographical

features destroyedno

discernible germinal centers

The same HIV-positive

patient after 6 monthson ARV treatment

Germinal centers discernible

again but lack healthy

surrounding mantle

Photos and information courtesy of Timothy Schacker, University of Minnesota


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Without ARVs, many non-HIV OIs can

be cured or prevented cheaply

Tuberculosis

Pneumocystis Carinii

Pneumonia

Thrush (candidiasis)

Cyrptococcalmeningitis

Can be prevented short-termwith INH. Cured withcombination antibiotics.

Can be prevented withCotrimoxazole (Bactrim) and

cured with that and otherantibiotics.

Can be cured with fluconazole.

Can be cured and preventedfrom recurring withfluconazole.


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So why is there novaccine against,

or a cure for,HIV/AIDS?

U f t t l th


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Unfortunately, these are some

of the responses

The virus is incredibly complex and operates in a

way rarely seen before

Theories about how HIV operates have all had

failings Drug development takes time, and is expensive.

When testing a new drug, the risk to the

individual trial patient must be weighed against

the hoped-for benefit

Global HIV Vaccine Enterprise


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So until medicine andscience can give us the

answer We have to look at ways to

prevent HIV infections & AIDS


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HIV/AIDS

As A

Public Health Issue


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Incidence the number of new cases arising in a given populationin a given time




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Incidence the number of new cases arising in a given populationin a given time



A very informal way of


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A very informal way oflooking at HIV transmission

You have to do something

Or have something done to you To contract HIV


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Vulnerable Groups

Local communities

National defense

Migrant workers

Agriculture

Education


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Until we have a vaccine

or a cure We have to focus on prevention


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Personal Prevention

Condoms Male or female

Microbicides

Limited sexual partners

Clean needles

male circumcision, for adults


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Societal Prevention

Developing of new drugs

Distribution of those drugs

Preventing mother-to-child transmission

Development of Vaccines

Sterile clinical environments

Government & industry attitudes


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Medicine & Public Health

Compared for the

Benefit of Journalists

Medicine Public Health


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Medicine Public Health

Primary focus onindividual

Diagnosis & treatment

Medical care

Social sciences as anelective part of PHeducation

Laboratory & bedside

Primary focus on population Emphasis on prevention Interventions aimed at

environment, behavior,lifestyle, medical care

Social science as an integralpart of PH education

Laboratory & field work

(after H. Fineberg, 1990)

L di C f D th


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Leading Causes of Death

In the United States

In the Year 1900

Influenza

Pneumonia

Tuberculosis

Gastritis Heart Disease

Cerebrovascular Diseases

Chronic Nephritis

Accidents

Cancer and other Malignant

Tumors

Early Infancy Diseases

Diphtheria

In the Year 2000

Tobacco

Poor Diet and PhysicalInactivity

Alcohol Consumption Microbial Agents

Toxic Agents Motor Vehicle Crashes

Incidents involving Firearms Sexual Behaviors Illicit Use of Drugs


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And if youre going toview them as both, then

you need two more basicdefinitions


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Journalism Practice


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I believe that AIDS is


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I believe that AIDS iscurable

Despite all the failed vaccine trials

Despite the failed scientific interventions

Despite the difficulties at prevention


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HIV/AIDS is curable

through education


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Journalists are educators

We research difficult situations

We show people what we have learned

We give them information

so they can improve their lives

so they can improve society

Because we are educators,


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Because we are educators,and given

The size of the epidemic

The potential for its growth

The impact on society

The impact on people

And the fact that print, or


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p ,broadcast & online

journalists cover everythingfrom .

Poor people

Rich people National defense

Marginalized

populations Sex workers

Our countrys future


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Then I think we caneducate manysegments of the

population about whatwe know.


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Thank you!

Acknowledgements


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Acknowledgements

Mark Schoofs, The Wall Street Journal Anthony S. Fauci & Greg Folkers, NationalInstitute of Allergy and Infectious Diseases

Bruce D. Walker & Marylyn Addo,

Massachusetts General Hospital, HarvardMedical School, Partners AIDS ResearchCenter

Timothy Schacker, University of Minnesota

Laurie Garrett, Newsday, & Omololu Falobi,Journalists Against AIDS Nigeria

Howard Hughes Medical Institute


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bob meyer's hiv/aids reporting refresher course

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