Weakened Live-Virus HIV Vaccine Could Raise Death Rates in Less-Affected Countries
The use of an attenuated live-virus HIV vaccine may "greatly" decrease mortality in countries with a high AIDS rate, but could actually increase death rates in countries where the AIDS epidemic is "low or moderate," according to a "sophisticated mathematical model" created by a research team at the University of California-Los Angeles. A vaccine using a weakened strain of live HIV could be "instrumental" in fighting AIDS as the vaccine may generate strong immunity, but it could also cause the disease in some vaccinated people, creating a medical "Catch-22" situation, Reuters Health reports. The researchers used the current AIDS death rates in Zimbabwe, where 25% of the population is infected with HIV, and Thailand, where only 2% of the population is infected. The study found that a live-virus vaccine would eliminate naturally occurring strains of HIV in both countries within 50 years, but would cause more than 5% of the population in Thailand to develop AIDS over 25 years. In Zimbabwe, the researchers predicted that more people would die of AIDS without a vaccine than with a public vaccination effort using live HIV. "The vaccines have the potential to do a great deal of good, but they also have the potential to do harm," lead researcher Dr. Sally Blower said, adding, "You can develop very effective vaccines. But they may well be the ones that are the least safe. There may be a trade-off that people will have to consider between efficacy and safety once these vaccines have been developed." To not use such a potent vaccine could mean "letting the entire continent of Africa be totally destroyed," she said, but asked, "Should you kill some people for the greater good of the rest of the people? That is a huge, huge ethical debate." The study, published in the Proceedings of the National Academy of Sciences, did not advocate vaccine use, but served to "provide a theoretical framework for predicting the outcome of using 1,000 different potential versions of such a vaccine," Blower explained (Dunham, Reuters Health, 3/13). Because of the risks, live-virus vaccines currently would not be approved for use by regulatory agencies, but contributing researcher Professor John Mills of Melbourne, Australia's Macfarlane Burnet Center said the study results show that live attenuated HIV vaccines "should be pursued as a means of globally eradicating HIV," despite the risks. He added that it was likely that the vaccines would provide the most benefit in countries where the prevalence of HIV was greater than 10% (Fannin, The Age, 3/14).This is part of the KHN Morning Briefing, a summary of health policy coverage from major news organizations. Sign up for an email subscription.