Yet another clinical trial for a vaccine to prevent HIV has failed, and for 48 men and transgendered individuals it meant that they contracted the virus while participating in the study. The study, which included 2,504 people, 215 of whom live in San Francisco, has been halted after four years because of the alarmingly high rate of HIV infections among those who received the vaccine, versus those who received a placebo.

In total, 27 people tested positive who had received the vaccine in 2009, while 21 people tested positive who had received the placebo. This could just be a statistical anomaly, but researchers decided that the results were too bad to keep the study going any longer. The study was known as HVTN-505, and was federally funded to the tune of $77 million. Though participants won't be receiving any further vaccine (or placebo) shots, they will be followed for another five years as part of the study.

Though this drug wasn't intended to be licensed for public use, it was part of the ongoing research into finding an effective vaccine, and doctors involved say that this was still an informative step in that process. As Dr. Susan Buchbinder, director of Bridge HIV which does clinical trials for the SF Department of Public Health, puts it to the Ex, "As we learn more information we try to revise each vaccine. And that way we inch closer toward a more effective vaccine."

Update: Reader Rustin Zomorodi, a trial participant and volunteer HIV counselor, took exception with our use of the word "alarmingly" above, and with the sensational nature of the coverage of the end of this clinical trial in general. His comments in defense of the study are below:

This study, like most clinical trials, was blind -- meaning that nobody knew whether they were receiving a vaccine or placebo, and thus, the "vaccine group" wouldn't be tricked into acting any less safely in their sexual choices as a result of believing they might be immune. Throughout the study, we were advised that it would most likely not be an effective vaccine and that it is only an early-stage test version. The results would be a step in the right direction, as even a failure to prevent infection would provide useful information (i.e. what strategies will not work).

As for the results themselves, 27 infections for the vaccine group vs. 21 in placebo is NOT an alarming difference, and 48 infections out of over 2500 participants is not higher than would be expected considering the study specifically targeted higher-risk populations. Their whole goal was to figure out if the vaccine would lower infection risk, so of course they selected participants who would have higher chances of contracting it (otherwise they would be wasting money and resources on participants that would provide no useful data). The trial was stopped because the vaccine group didn't show any reduction in risk (as hoped for), but the difference seen between groups is NOT large enough to be statistically significant given the size of the study. This means the results do NOT show that the vaccine increased risk. If anything, the extremely regular testing, HIV education and comprehensive risk reduction counseling most likely lowered the risk for infection among the high-risk populations that were included, as has been seen in MANY other clinical trials for HIV prevention strategies (like Truvada for use as pre-exposure prevention, or PrEP). We were not misinformed and tricked into thinking that this trial vaccine was anything like PrEP, which has in the past been proven to work against infection but is still undergoing further trials here in the Bay Area.