[BRIEF NOTE] Towards a HIV vaccine?

[rfmcdonald]

The CBC was one news agency of several to report on news that the mechanisms behind a promising partially effective HIV vaccine being tested in Thailand--I wrote about it in 2009--are becoming understood.

At the AIDS Vaccine conference in Bangkok on Tuesday, scientists announced an update to a Thai trial of a "modestly effective" experimental AIDS vaccine.

At the end of the initial 3½-year study, the vaccine prevented infection in about 30 per cent of the 16,000 Thai volunteers who received it compared with a placebo.

The new findings shed light on how the vaccine worked by identifying how the immune system responded to it.

[. . .]

Stephen Kent, a vaccine researcher at the University of Melbourne, described the antibodies produced by the vaccine as "friends with benefits."

"They don't necessarily prevent infection of cells but it allows them to kill infected cells," said Kent. "So it may be that that really helps protection."

[. . .]

Scientists want to take the findings back to the lab or clinic to try to improve the effectiveness of the Thai vaccine. Results suggested that protection against HIV appeared highest at six to 12 months, which investigators hope to sustain or boost.

But the vaccine and the immune response it created were specific to the type of HIV in Thailand, and the vaccine formulation used there, scientists cautioned.

The findings suggested the vaccine had no effect on the amount of virus in the blood of those who became infected with HIV. Vaccination did seem to be associated with lower amounts of virus in genital fluids.

Even a partially effective vaccine like the one described above could be quite effective in altering the contours of the epidemic, especially with the decreased amount of HIV in genital fluids (i.e. plausibly decreased sexual transmission risks). If combined with near-universal treatment of HIV-infected people, as proposed, the number of transmissions could drop off hugely.