Trials of a promising AIDS vaccine in South Africa were halted earlier this week after a sister vaccine being tested on humans throughout North America showed it did nothing to prevent HIV infection.
In fact, according to the Seattle Times, the vaccine may well increase risk of infection.
Following the abandonment of the trials, South African AIDS researchers have begun contacting the hundreds of volunteers who took part in the trials over recent months, warning them the vaccine could well make them more, not less, likely to contract the virus.
The move comes on the heels of an announcement last month by Merck Co. that an AIDS vaccine they were developing possibly caused more infections than it averted.
Of those given the vaccine, 19 contracted the virus as opposed to just 11 who were given the placebo.
“This is my worst nightmare,” Glenda Gray, the lead South Africa investigator for the vaccine study, told the Washington Times.
“I haven’t slept for days. I have a headache. I’m ready to resign from trials for the rest of my life.”
According to the Times, researchers in Capetown began contacting the more than 800 participants in the study on Tuesday, most of them via text messaging.
The goal, which researchers are calling an “unblinding” of the trial, is to let each of the participants know whether they were given a vaccine or a placebo.
While researchers say that the vaccine could not have caused HIV infection, it is possible the vaccine caused changes in the immune system which would make the virus easier to contract during later infection.
In the United States the Merck vaccine trials took place in 15 cities including Boston, Los Angeles and New York.
Around the world, studies in Peru, Haiti and Australia were also conducted.
According to a spokesperson for Merck, most of the U.S. volunteers were gay men.
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