aids vaccines: the basics cindrafeuer avac: global advocacy for hiv prevention 20 april 2010 the hiv...

AIDS Vaccines: the basics

CindraFeuerAVAC: Global Advocacy for HIV Prevention20 April 2010The HIV Research Catalyst ForumBaltimore, Maryland

April 2010 www.avac.org/presentations

AIDS Vaccine Presentation Overview


• What is a vaccine?• How would an AIDS vaccine work?• Where are we in the search?• How to get involved?


• A substance that teaches the immune system how to protect itself against a virus or bacteria

• No effective AIDS vaccine available today

• AIDS vaccines cannot cause HIV• No vaccine is 100% effective. Most

vaccines licensed in the US 70%-95% effective.

What is a vaccine?

Why the interest in an AIDS vaccine?


• Need for a range of HIV prevention methods (There’s no silver bullet)

• Proven prevention options have slowedHIV’s spread but thousands of people continue to get infected daily

• Vaccines are one of the world’s most effective public health tools

• Cost-effective (administered once)

Types of AIDS vaccines


• Preventive Vaccines:– Designed for people who are not infected with HIV– Reduces risk of infection or viral load set point after

infection

• Therapeutic Vaccines: – Designed for people who are living with HIV– Uses the body’s immune system to control HIV in the

body

How does a vaccine work?


• By teaching the body to recognize and fight invaders– Subunit—small amount of virus or copy of virus in the

form of vaccine– Body reacts by creating antibodies or killer cells– Upon viral infection, antibodies and killer cells are there

waiting to attack

How a preventive AIDS vaccine would work


• Humoral– Antibodies

– Y-shaped proteins that look for HIV to stop it from infecting cells

– Adaptive immune system

How preventive vaccines would work (con’t)


• Cellular immunity– White blood cells or CTL– White blood cells that

look for HIV-infected cells and kill them

How an HIV vaccine might work


HIVHIVPREVENT ESTABLISHED INFECTION?

*****

VaccineAdministered

AA. Lower Initial Peak of Viremia

AA

BB. Lower Set Point

BB

C.C.Delay Progression

CC

HAART

How are most vaccines made?


• Live attenuated vaccines(examples: measles, mumps, and rubella)

• Whole killed virus vaccines (example: influenza and rabies)

How are AIDS vaccines made?


• Recombinant vaccines

• Do not contain HIV• DNA vaccines• Vector vaccines

Developing an AIDS vaccine is difficult


• Numerous modes of transmission

• HIV kills the very immune cells uses in defending the body against HIV

• HIV makes many copies of itself and mutates, making itself unrecognizable to the immune system

• Mutation leads to different subtypes of the virus throughout the world

Vaccine research in perspective

www.avac.org/presentations

Virus or bacteria Year cause discovered

Year vaccine licensed

Years elapsed

Typhoid 1884 1989 105

HaemophilusInfluenzae 1889 1981 92

Malaria 1893 None –

Pertussis 1906 1995 89

Polio 1908 1955 47

Measles 1953 1995 42

Hepatitis B 1965 1981 16

Rotavirus 1973 1998 25

HPV 1974 2007 33

HIV 1983 None –

Duration between discovery of microbiologic cause of selected infectious diseases and development of a vaccine

Source: AIDS Vaccine Handbook, AVAC, 2005

Timeline of results from AIDS vaccine efficacy trials


Thai prime-boost AIDS vaccine trial


The Thai trial: RV144


• First glimpse of evidence a vaccine has a protective effect• 31.2 % (modest effect)• Not for licensure• Research ongoing

Ongoing vaccine trials


• About two dozen safety and immunogenicity studies

• HIV Vaccine Trials Network (HVTN 505)

HVTN 505


• Phase II, uses a DNA prime/rAd5 boost (T cell-based)

• Currently recruiting circumcised MSM at sites across the US

• Parts of this vaccine regimen are similar to the vaccine used in Step and Phambili

• Reduce viral load in individuals who receive the vaccine and go on to become infected with HIV

HVTN 505 continued


• Not expected to prevent HIV infection• Not on the path to licensure • Better understand and develop T cell-based

vaccines • Like in all prevention research studies, all

participants will receive the best available prevention services

• Results expected 2013More information about HVTN 505: www.hopetakeaction.orgGet involved: www.bethegeneration.org; www.hvtn.org/about/sites/html; www.vaccineforall.org

http://www.hopetakeaction.org/

http://www.bethegeneration.org/

http://www.hvtn.org/about/sites/html

http://www.vaccineforall.org/

What is needed now?


• Vaccination to protect against infection, mitigate infection and prevent transmission to others

• Focus investigation to better understand the Thai trial result

• Ensure diversity of approaches beyond the Thai trial, exploring novel directions for vaccine design

• More community involvement

What can you do?


• Join a Community Advisory Board• Ask your local AIDS organizations if they are

aware of or involved in vaccine research• Support trial volunteers and recognize their

contribution to the fight against HIV/AIDS• Volunteer to be in a clinical trial

Stay informed


• Join the Advocates Network• AVAC publications: Px Wire, Anticipating and

Understanding Results series, AVAC Report• Attend events (AVAC calendar)

AVAC: Global Advocacy for HIV Prevention www.avac.orgInternational AIDS Vaccine Initiative www.iavi.orgHIV Vaccine Trials Network www.hvtn.orgGlobal HIV Vaccine Enterprise www.hivvaccineenterprise.org

http://www.avac.org/

http://www.iavi.org/

http://www.hvtn.org/

http://www.hivvaccineenterprise.org/

The search must go on


“... they are ill discoverers that think there is no land when they can see nothing but sea.”

— Francis Bacon (1561-1626)

aids vaccines: the basics cindrafeuer avac: global advocacy for hiv prevention 20 april 2010 the hiv...

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