Will the Thailand HIV vaccine work?

Oct 02, 2009

LAST month will always be known as the September, where scientists eventually got the vaccine that protects some people against HIV infection. After more than 25 years into the AIDS pandemic, scientists finally discovered a vaccine.

LAST month will always be known as the September, where scientists eventually got the vaccine that protects some people against HIV infection. After more than 25 years into the AIDS pandemic, scientists finally discovered a vaccine.

But instead of celebrating, they are going back to the drawing board. The vaccine, a combination of two older vaccines, only lowered the infection rate by about a third after three years, among 16,000 ordinary Thai volunteers. Vaccines need to be at least 50% effective, and usually 70 to 80% effective, to be useful.

But the bad news is that no one knows why it worked. “Additional studies are clearly needed to understand how this vaccine regimen reduced the risk of HIV infection,” Dr. Eric Schoomaker, surgeon general of the US Army, which helped pay for the study, told reporters.

“Results need to be fully understood to form the next steps in the development of a safe and effective HIV vaccine,” Dr. Peter Kim, president of Merck Research Laboratories, said in a statement.

Already, pharmaceutical companies, which say they are fascinated by the vaccine, are still fearing the business proposition as too risky. “What is needed is more in-depth analysis, to extend these findings, doing both clinical (human) and preclinical (animal) studies to find out why it is working and how we can make it better,” Jim Tartaglia, vice president of research and development at Sanofi, told reporters.

Companies and NGOs along with governments have been working to make a vaccine against HIV and experts agree that a vaccine is the only way to conquer it.

But the virus mutates unbelievably fast, can hide from the immune system and attacks the very cells sent to battle it. To work, any HIV vaccine would have to activate both arms of the immune system, the antibodies that come in on invaders such as viruses to neutralise them, and the T-cells that recognise and destroy viruses.

This vaccine did not appear to generate much of either response, and yet prevented infection 30 percent of the time.

The findings do offer renewed hope for finding a vaccine.

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