One step on the road to an AIDS vaccine

We have long known that it takes a combination of drugs to keep AIDS in check. Combination therapies have transformed what was a death sentence into a chronic condition. (Image from Healthandmedicines blog.)

It seems that same approach may also, in time, deliver a vaccine. One step along that road was announced today, the results of a trial in Thailand that cut the risk of successful infection by about one-third.

Over 16,000 volunteers were given six injections, one per month. Some were given a series of AIDS vaccines, including ALVAC and AIDSVAX. Others were given a placebo. Over 6 years 74 of those who got the placebo were infected, against 51 of those given the vaccine.

This was deemed a "very important result"  because previous trials of AIDS vaccines were complete failures.

Note we are not talking about a success. A vaccine isn't considered successful unless it cuts the risk of infection by at least 70-80%.

And the viral load in those infected on the placebo was no different than with those infected while on the vaccine, indicating true AIDS "antibodies" were not developed.

Critics of the study, contacted by Science Magazine, were cautiously pessimistic, wanting more data and detail before admitting they might have been wrong. Their active skepticism is important, even if it turns out to have been misplaced, because without it results can't be tested rigorously.

The study was criticized because people feared it might lead to actual infections, and because the medicines in the trial had not proven to be effective at all previously, yet were moving into a larger study.

What we have, in the end, is an intriguing result that could open up new avenues in the search for a real vaccine.

The sufferings and risks taken by the Thai volunteers they have delivered a hunch. But that's more than we had before.

This post was originally published on Smartplanet.com