SEATTLE, Nov. 8 (UPI) -- Researchers meeting in Seattle say a failed AIDS vaccine may have increased the risk of test participants getting HIV.
The New York Times said the patients who face the highest risk are those who had pre-existing levels of immunity to a common cold virus known as adenovirus type 5.
Merck halted the trial of its experimental HIV vaccine in September.
The vaccine was tested among 3,000 volunteers at high risk of developing AIDS in nine countries, including the United States. AIDS researchers are calling the failure a major setback.
In September, a preliminary analysis found that there were 24 HIV infections among those vaccinated compared with 21 who received a placebo. Among 778 male volunteers who had a high level of pre-existing adenovirus immunity, 21 of those receiving the vaccine developed HIV compared with nine in the placebo group.
