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rfmcdonaldMost of you have probably heard the very encouraging news about the development of what might be the first partially successful HIV vaccine.
This is a spectacular achievement, even if it is only partial. This observation, arguing that "the first HIV vaccines licensed for use may be only partially effective and may act in three ways: (1) by preventing some but not all vaccinated persons from becoming infected (“partial efficacy” or “reduced susceptibility” to HIV infection); (2) by lowering a vaccinated individual's infectiousness (and thus his or her ability to infect others); and (3) by reducing the rate at which an individual would progress to AIDS disease if infected with HIV", seems prescient. As noted in this this Council of Foreign Relations roundtable summary, even a partially effective HIV vaccine could be useful.
A suggestion has been made that the vaccine could be delivered first to high-risk groups. As a member of such a high-risk group, I'd be more than happy to take the shot(s) in the arm. I'd even be quite happy to pay for it. Partial efficacy is better than none at all, and anything that gives me legitimate cause to let my ongoing paranoia re: HIV to slip is a good thing.
And you?
A U.S.-funded study involving more than 16,000 volunteers in Thailand found that a combination of ALVAC, made by Paris- based Sanofi-Aventis SA, and AIDSVAX, from VaxGen Inc., of South San Francisco, cut infections by 31.2 percent in the people who received it compared with those on a placebo, scientists said today in Bangkok. Neither vaccine had stopped the virus that causes AIDS when tested separately in previous studies.
The finding represents a revival in a campaign that appeared to stall just two years ago when use of Merck & Co.’s experimental Ad5 vaccine boosted some people’s chances of infection in a study. The latest result will transform future research, said Mitchell Warren, director of the New York-based AIDS Vaccine Advocacy Coalition.
“Wow,” said Warren, who was not involved in the study, in a telephone interview today. “We are in a new place in the search for an AIDS vaccine. It’s safe to say that the scientific community is caught off-guard.”
The findings don’t mean the vaccine can be delivered worldwide, because of unanswered questions about how the vaccine worked and the fact that it was designed using HIV strains that are specific to Thailand, said Anthony Fauci, director of the National Institute of Allergy and Infectious Disease in Bethesda, Maryland. It will take years of research before a vaccine might be ready for U.S. approval, he said.
[. . .]
Sanofi’s ALVAC uses a canarypox virus that’s been disabled so it doesn’t cause sickness in humans to smuggle three HIV genes into the body. It’s designed to coax the immune system to make so-called T-cells, protectors that hunt and kill infection deep inside the body.
The AIDSVAX shot contains an HIV protein called gp120 that’s used by the virus to enter human cells. It is designed to encourage the body to produce neutralizing antibodies to destroy HIV viruses before they can infect healthy cells.
The search for a vaccine to prevent HIV has eluded scientists since the early 1980s. AIDS, the syndrome linked with HIV, infects about 6,800 new people globally every day. While there are treatments for HIV that limit the virus in the body, holding AIDS at bay for years, there is no cure.
This is a spectacular achievement, even if it is only partial. This observation, arguing that "the first HIV vaccines licensed for use may be only partially effective and may act in three ways: (1) by preventing some but not all vaccinated persons from becoming infected (“partial efficacy” or “reduced susceptibility” to HIV infection); (2) by lowering a vaccinated individual's infectiousness (and thus his or her ability to infect others); and (3) by reducing the rate at which an individual would progress to AIDS disease if infected with HIV", seems prescient. As noted in this this Council of Foreign Relations roundtable summary, even a partially effective HIV vaccine could be useful.
In 2009, the preliminary results from two leading AIDS vaccine trials will be released. Both trials, one by Sanofi Pastuer and the other by Merck in collaboration with the National Institutes of Health (NIH) aim to boost T-cell immune responses. If the results from the Sanofi and Merck trials reveal that the HIV vaccine is only partially effective, and cannot significantly slow the spread of HIV within vaccinated communities, it begs the question “how good is good enough”, Warren commented.
An HIV vaccine with 50% efficacy, if administered to only 30% of the target population could still avert up to a third of new infections from occurring and therefore save tens of millions of lives, Berkley insisted, citing modeling studies done by IAVI.
“Even vaccines that don’t totally prevent infections and don’t work 100% of the time can be extremely useful vaccines,” Robertson said.
A suggestion has been made that the vaccine could be delivered first to high-risk groups. As a member of such a high-risk group, I'd be more than happy to take the shot(s) in the arm. I'd even be quite happy to pay for it. Partial efficacy is better than none at all, and anything that gives me legitimate cause to let my ongoing paranoia re: HIV to slip is a good thing.
And you?
