DR Peter Figueroa on Thursday pleaded with United States ambassadors to the Caribbean not to turn down immigrant visa applications for volunteers participating in the vaccine trial who test positive for HIV, as some non-infected participants were getting false positive results.

Dr Figueroa, the chief of epidemiology and AIDS in the Ministry of Health, told the ambassadors attending the Sixth Annual United States Chiefs of Mission Conference on HIV/AIDS in Kingston, that the issue of the false result was one of the challenges faced in the trial.

“I just want to alert the chief of mission that with the vaccine trials being done. we do have a situation that some of our people could be getting the experimental vaccine and they could test positive on their regular HIV test if they come to do a permanent visa medical,” said Dr Figueroa.

“We want you to be aware of this because the vaccine trial network has labs that can do the test in a way that can be sure if it is a false positive,” he added.

According to Dr Figueroa, not all vaccine trials were expected to work, but said there were strict monitoring, which was the reason the recently failed trial was stopped early.

“.The group of scientists monitoring the results found it was not effective in that equal numbers in the vaccine group or the placebo group were becoming infected,” he said.

He reiterated, however, that there were no serious adverse effects from the vaccine itself.

Last week, New Jersey-based Merck & Company suspended worldwide enrolment and vaccination of volunteers in the study, which was partly funded by the United States National Institutes of Health.

According to an Associated Press report, Merck’s vaccine was the farthest along and was closely watched by experts in the field, anxious to find a cure for one of the world’s cruellest killers. A total of 3,000 volunteers worldwide had the vaccine administered to them.

The Merck vaccine, known only as V520, was also being tested in a similar study in South Africa and in two smaller studies, which were also halted.

Officials at the company, based in Whitehouse Station, New Jersey, said 24 of 741 volunteers who got the vaccine in one segment of the experiment later became infected with HIV, the virus that causes AIDS. In a comparison group of volunteers who got dummy shots, 21 of 762 participants also became infected.

The volunteers in the experiment were all free of HIV at the start. But they were at high risk for getting the virus as most were homosexual men or female sex workers. They were all repeatedly counselled about how to reduce their risk of HIV infections, including the use of condoms, according to Merck.

Volunteers had to meet a long list of criteria in order to be accepted for the trial. The key requirements included an age limit of 18 to 45 years and in good health.