Basic Concepts about AIDS Vaccine Research

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Condoms Arenâ€&#x;t Enough! Will Pills and Lubes Define the Future of Sex? An Overview of New HIV Prevention Tools in Development


An Overview of New HIV Prevention Tools in Development •Vaccines – Dr. Gaudensia Mutua • PrEP – Dr. Jorge Sanchez • PrEP – Dr. Patrick Wilson •Rectal Microbicides – Dr. Ian McGowan Test and Treat, TLC+, Treatment as Prevention

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Dr. Jorge Saavedra Dr. Roger Tatoud


Basic Concepts about AIDS Vaccine Research Dr. Gaudensia Mutua Kenya AIDS Vaccine Initiative & International AIDS Vaccine Initiative Vienna, 17th July 2010 MSM Global Forum


We need a range of prevention tools, including an AIDS vaccine 2008

2005

33 million

32 million 2000

28.5 million

1990

7.5 million PLWHA

1995

18.5 million

HIV continues to devastate even with current programs Prevention options don’t meet everyone’s needs Women bear the brunt of the epidemic Source: Joint United Nations Programme on HIV/AIDS


What is a typical immune response to infection? Individuals usually mount an effective response against a pathogen Viruses and bacteria can cause significant illness, but most of the time, a person recovers and clears the virus or bacteria from their body After natural infection, you develop immunity that protects you from getting sick again if exposed to the same bug

This protection is usually complete and lifelong


HIV is different… HIV hides in host cells HIV is very diverse and mutates easily (keeps changing) HIV can avoid a protective immune response by “hiding” some of its internal parts HIV destroys the immune cells that should help to protect against the infection


Some scientific challenges… Short window of opportunity to respond before HIV integrates in the cell •That means that the vaccine must be able to generate an immune response at the first point of contact – Genital regions

Natural immune responses do not kill HIV, unlike immune responses to other viruses or bacteria • That means that we do not know what kind of immune response can protect against HIV infection or AIDS (we do not know the “correlates of protection”)

Traditional methods to make vaccines cannot be used for HIV vaccine research due to safety concerns • That means entirely new methods need to be designed that only uses parts of HIV – we do not yet know which parts are important • Limited animal models for HIV vaccine research


Clues that may help provide insight Clues from HIV-infected individuals Long-term non-progressors • HIV-positive, but controlling virus without antiretroviral treatment Acute Infection • Learning about early immune responses • How HIV changes to „escape‟ the early immune responses People with broadly neutralizing antibodies • Finding these antibodies that can recognize and eliminate many HIV variants

Clues from uninfected people Exposed seronegative • Despite exposure to HIV remain seronegative • Develop some immune responses over time People who received experimental vaccines • Which immune responses do and which do not provide a benefit


An AIDS vaccine is possible

A recent study showed for the first time in people that an experimental vaccine could provide a modest level of protection against HIV infection


The Thai trial‌


RV144 trial: The Results Chiang Mai

Vaccine candidate provided ~30% protection against acquisition of HIV; No effect on disease progression in the blood of volunteers who became HIV-infected during the study

Tak

T H A I LA N D Bangkok

• Trend towards limited durability; vaccine effect appears short lived

Trial sites:

Rayong Province

• Vaccine likely not applicable to diversity of strains prominent in sub-Saharan Africa

Chon Buri Province HIV clade E is predominant in these regions Phuket


Research with community involvement • Voluntary Counseling & Testing (more than 12,000 tested/per year) • Community education on HIV prevention and clinical research • National AIDS Vaccine Plans (Kenya, Uganda) • Support to community VCT and healthcare centers • Community medical camps • Strengthening of regulatory capacity for clinical trials


Reaching Under-served Populations •

Personalized risk assessment and risk reduction counseling HIV & STI information tailored to the needs of MSMs* Provision of condoms and

water based lubricants •

Other risk groups- IDUs and Female sex workers •

Family Planning

*Brochure courtesy of Dr. Eduard Sanders (KEMRI-KILIFI)


HIV Vaccine Research in Context: Pathogen

Years to develop vaccine

Typhoid

105

Haemophilus influenzae (HIB)

92

Pertussis (whooping cough)

89

Polio

47

Measles

42

Hepatitis B

15

HIV Adapted from Markel, New Engl J Med, 2005; 353(8): 753-7.

25 + ?



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