Transcript Basic Definitions - ICAD-CISD

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New Prevention
Technologies
Workshop
Module 1:
Basic definitions
Objectives
This workshop will:
 Increase the capacity of media representatives to
report on NPT trials with accuracy and sensitivity
 Build skills amongst community-based
organizations to critically analyze media discourse
about HIV prevention trials
 Increase the capacity of community representatives
to understand and communicate NPT trial results
effectively
Warm-Up Exercise
Please read the articles that have been provided
to you. They all report on the same trial results.
Discuss Questions:
1. What is the tone of each article? (Optimistic?
Pessimistic?)
2. What conclusion do you come to after reading
each article?
3. What information do you feel is missing?

Imagine a full spectrum of
interventions
Point of
transmission
Prior to exposure



Rights-focused behaviour
change

Male & Female condoms
and lubricant
Voluntary counselling &
testing

Treatment to prevent
vertical transmission
(PMTCT)
Sexually transmitted
infection screening
and treatment

Male medical circumcision

Preventative vaccines

Pre-exposure prophylaxis
(PrEP)
After infection

Antiretroviral treatment

Treatment for opportunistic
infections

Basic care/nutrition
Prevention for positives

Clean injecting equipment


Post-exposure prophylaxis
(PEP)

Education and rightsfocused behaviour change

Vaginal & rectal
microbicides

Therapeutic vaccines

Functional cures

Cervical barriers
Which NPTs?

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Vaccines?
PrEP?
Microbicides?
Medical male circumcision?
Female condoms?
Treatment-as-prevention?
MEDICAL MALE
CIRCUMCISION
Medical male circumcision



3 studies conducted: South Africa, Uganda, Kenya
Trials showed: circumcised men about 60% less likely to
acquire HIV through unprotected vaginal intercourse
WHO published recommendation based on study results
Medical male circumcision


60% risk reduction for HIV-negative circumcised men
during unprotected vaginal intercourse with HIV+
woman
Trials did not show reduction in transmission risk from
circumcised HIV+ man to HIV-negative woman


In fact, one trial showed opposite trend: increased risk for
wives of circumcised HIV+ husband; probably due to
resuming sex too soon after circumcision
Trials did not provide information on effect of
circumcision on HIV transmission during anal sex—for
either women or men
Challenges with Male Circumcision

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Public messages must be communicated very clearly:
reduces but does not eliminate men’s HIV risk
Need to educate about the difference between FGC and
male circumcision
“Potential harmful outcomes”: condom substitution,
surgical complications, inadequate healing time
Religious and cultural meanings of circumcision
Ethics of promoting circumcision for infant boys
FEMALE
CONDOMS
Female Condoms
Or “the internal condom”

a thin pouch that a woman can insert in her vagina before sex
to prevent pregnancy and sexually transmitted
infections (STIs), including HIV

FC1: Polyurethane; FC2: nitrile rubber (less noisy, cheaper than
FC1)

the only proven, female-initiated method of HIV
prevention currently on the market

can be used vaginally or anally

same efficacy as male condoms for STI prevention and
contraception
Challenges with Female Condoms
Almost all (99.6%) condoms distributed globally are male
condoms. Only a tiny fraction of women worldwide have
access to female condoms. Why?

High price: US$0.60 vs. US$0.04 for male condom

Perceived and real acceptability
issues: cumbersome, hard to use, partners do not like them,
taboos around female sexuality

Not enough donor and policy-maker support: low interest
among some major donors and governments

Discomfort among “gatekeepers”: health care providers
and HIV and AIDS programme implementers
ARV-BASED
PREVENTION
METHODS
ARV-based prevention options
Point of
transmission
Prior to exposure
After exposure
Preventing vertical transmission (PMTCT+)
PrEP
Treatment of HIV+
partner
Vaginal microbicides (rings)
Vaginal microbicides
(gels) and rectal microbicides
PEP
HIV prevention
Not ARV-based


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Male & female
condoms
Circumcision
Clean injecting
equipment
Vaccines
VCT


ARV based
Vaginal and
rectal
microbicides
Preventing
vertical
transmission

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PEP
PrEP
Treatment for
HIV+
partner
Comparing ARV-based prevention
methods
PEP
Drugs
used
Delivery
formats
Multiple
ARVs
Oral pills
Frequency Daily for 4
weeks
of use
Preventing
vertical
Treat HIV+
transmission
partners
(PMTCT)
PrEP
Microbicides
Tenofovir and
Truvada
Tenofovir, TMC 120
(daviripine), UC781,
MV-150
Nevirapine;
combination, if
possible
(AZT+3tc+
nevirapine)
Multiple ARVs
Pills, dropper
Oral pills,
injection
Oral pills
Vaginal and rectal
gels with applicators,
vaginal rings, film
At least daily
At least daily,
possible
dosing related
to exposure
Before and possibly
after sex, possibly
daily dosing
Varies from
ongoing
treatment to
doses just before,
during, after
delivery
Why test ARVs to prevent HIV?

ARVs already are used to prevent vertical
transmission (or PMTCT)

PEP already is used to prevent infection after
medical accidents or rape

Monkeys that get ARVs prior to exposure are less
likely to be infected with “monkey forms” of HIV
TREATMENT AS
PREVENTION
Treatment as prevention
HIV+ people taking ARVs regularly

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Does it work at individual level?
 Treatment = less virus = less transmission
Can it work at population level?
 Increased testing = more knowledge of status = less
risk-taking
 Increased testing = more HIV+ people on treatment =
less virus
 Less risk-taking + less virus = less transmission?
Steps needed for
“Treatment as prevention”
ARVs
for
prevention
Access to treatment
Knowledge of status
MICROBICIDES
VIDEO
What is a microbicide?
A suppository or a gel applied
with an applicator before sex
A vaginal ring that stays in place
for up to a month
We need microbicides that:
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Are both contraceptive and not contraceptive
Help reduce the risk of getting other sexually
transmitted infections
Are inexpensive and easily available
Can be used without a partner’s active
cooperation
Can be used vaginally or rectally
Can be used by HIV+ people (products not based
on ARVs)
Why would HIV+ people want
microbicides?
To reduce the risk of co-infection with other
HIV strains.
 To reduce the risk of other sexually
transmitted infections, and yeast and
bladder infections
 To allow conception whilst protecting
partner

1. Boost vagina’s
natural defences
2. Surfactants
*
5. Future possibility 4. Stop replication
3. Block binding
*STDs: sexually transmitted diseases
Comparing ARV-based and
non-ARV-based microbicides
ARV

More potent against
HIV
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May be long lasting

Not contraceptive
Advantages
Disadvantages

May be more toxic

May cause resistance

Unlikely to protect
against other sexually
transmitted infections
Not ARV

Could work against HIV
and other sexually
transmitted infections

Could be contraceptive
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May be less potent
against HIV

Must be used at time
of sex
PRE-EXPOSURE
PROPHYLAXIS
Pre-exposure prophylaxis (PrEP)
Experimental HIV prevention strategy that would use
ARVs to protect HIV-negative people from HIV
infection
Taking medicine to prevent rather than to treat a
disease or condition.
For example:
 Taking pills to prevent malaria when you travel
 Using hormonal contraceptives (injections or pills) to
prevent pregnancy
 Taking pills to avoid pneumonia, if you are at risk
What makes a drug a good
candidate for PrEP?
Now being tested:
tenofovir (Viread)
Truvada (tenofovir+emtricitabine combined)
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Easy to use: Only one pill required per day
(maybe less)
Safe: Few side effects in HIV-positive people
Powerful: Stays in the bloodstream a long time
Unique resistance profiles: If resistance
develops, other treatment options still exist
Safety concerns?
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Safety is a critical issue for PrEP use
Look carefully at people with pre-existing conditions:
hepatitis B and C, kidney problems, bone density
Pregnancy, post-menopause (osteoporosis),
adolescents (bone formation)
Look carefully at drug clearance in people with low body
weight, including women and Asians
ISSUES AROUND
ARV-BASED
PREVENTION
METHODS
Drug resistance
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More likely if taking only one drug
(or one type of ARV)
Can still become HIV+ using
ARV-based prevention
Use by people who don’t know they
are HIV+ might lead to resistance?
Options for treatment may be more limited, might pass
on resistant virus
Unanswered questions at this point
Think of weeds in a garden
If you use weed killer:
 Some weeds die
 Others thrive, grow
bigger, and take over
 The weed killer
accidentally helps
resistant weeds – it takes
away all their competition
To stop the big weeds:
 Take away the first weed
killer
 Introduce other weed
killers that stop all weeds
– big and small
Concept for this slide:
Jeanne Marrazzo, MD
and John Mellors, MD,
MTN
Next steps for science
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Gather more data on how PrEP works across
populations
Address safety concerns through current trials and
further research
Learn how to monitor widespread resistance
Study intermittent use: for example, taking it only when
you expect to have sex.
Find out about impact on pregnancy and breast feeding
Test other ARVs to see if they might also work as PrEP
IMMUNE SYSTEM,
HIV AND VACCINES
VIDEO
Vaccines

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A vaccine is a substance that teaches the body to
recognize and defend itself against bacteria and viruses
that cause disease.
A vaccine causes a response from the immune system—
the body's defense system—preparing it to fight, and
also to remember how to fight, if exposed to a specific
infection.
A vaccine is not a cure, but prevents infection or slows
disease progression.
A vaccine primer
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200 years of vaccines
Common vaccines
Types of immunity: humoral (antibody) and cellmediated
An ideal HIV vaccine
Preventative or therapeutic?
Immune response
Challenges in HIV Vaccine Research
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Designing the vaccine: need a different approach
for HIV vaccines
Animal models: have not yet accurately predicted
how they will work in humans
Unknown correlates of protection: don’t know
what immune responses will protect an individual
from infection
HIV mutation: there are many different subtypes of
HIV, may require matching vaccines
…but on the bright side…
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Broadly neutralizing antibodies found
Precedent from other systems:
Success against other viral infections
Precedent from animal studies: Longterm control of infection in
vaccinated monkeys
Immune control of HIV-1: Infected
individuals control infection
Vaccine trials: In progress
GENDER
IMPLICATIONS
Gender and HIV
What do we mean by “gender”? Is it the
same as “sex”?
 What factors influence vulnerability to HIV?
 What impact does gender have on HIV
prevention?
 For women?
 For men? For gay men?

What women need to protect
themselves
Social power
Protection
Technology
Economic
opportunities
Questions women have about ARVbased prevention
If I think my husband
has HIV, will I be able
to get PrEP?
Even if the doctor
gives me pills, will I
be able to keep
them for myself?
If I use a
microbicide,
how will I make my
man use a condom?
More questions women have
People will notice if I
have to go in for
testing and to get my
pills. What will they
say about me?
Will my husband
let me go to the
clinic?
How much
will it cost?
Where will I get it?
Will it make
me sick?
Can I take PrEP when I
am pregnant?
Will it hurt my baby?
What about
breastfeeding?