Factbox: Vaccines: the Holy Grail of AIDS research

VIENNA (BestGrowthStock) – A major international conference on AIDS starts in Vienna on July 18, when thousands of scientists, health workers, activists, and government officials will gather to discuss the latest advances against the disease.

There are many drugs to treat HIV and prevention and measures have been deployed try to stop its spread, but so far there is no vaccine against the human immunodeficiency virus that causes AIDS.

However, this year’s meeting comes as optimism among scientists about the prospect of developing vaccine is at its highest for a decade.

Here are some facts about the search for an AIDS vaccine, and some of the recent developments in the field:

* The AIDS virus is difficult to fight in part because it attacks immune system cells and in part because it is constantly mutating, making it a constantly moving target

* Researchers have been looking for parts of the virus that do not mutate so they can design vaccines that will protect against these constantly changing versions.

* In July 2010, researchers in the United States discovered antibodies that can protect against a wide range of AIDS viruses and said they may be able to use them to design a vaccine.

* In September 2009, researchers reported their biggest success yet with a vaccine that appeared to slow the rate of infection by about 30 percent in Thai volunteers, but the researchers have since described the effect as “weak” and “modest.” The vaccine is a combination of Sanofi-Aventis ALVAC canary pox vaccine and the failed HIV vaccine AIDSVAX, made by VaxGen and owned by a non-profit group called Global Solutions for Infectious Diseases.

* Also in September 2009, U.S. scientists said they had found two antibodies against HIV, called PG9 and PG16, which are known as broad neutralizing antibodies and can block the ability of a relatively large number of HIV variants to infect cells.

* There are currently around 100 clinical trials of potential AIDS vaccines going on around the world, but many of them are in the very earliest stages.

* Even a vaccine that is not 100 percent effective or is not given to 100 percent of at-risk populations could have significant benefits. According to the International AIDS Vaccine Initiative (IAVI), a vaccine that is 50 percent effective and given to just 30 percent of the population could cut the number of new HIV infections in developing countries by 24 percent over 15 years.

* SOURCES: Reuters, IAVI

(Writing by Kate Kelland, editing by Elizabeth Fullerton)

Factbox: Vaccines: the Holy Grail of AIDS research