Researchers have developed a new, easy-to-administer vaccine that protects monkeys against the AIDS virus, bringing scientists one step closer to an effective vaccine for humans. The findings appear in the September 7 issue of the journal Cell.

The novel vaccine, designed by John K. Rose of Yale University and his colleagues, uses a weakened form of a common livestock virus known as vesicular stomatitis virus to deliver AIDS virus proteins to the body. These proteins stimulated a strong immune response in seven monkeys that received the vaccine: 14 months after the researchers infected them with the AIDS virus, the vaccinated monkeys remained AIDS-free. Seven of eight unvaccinated monkeys, in contrast, developed the disease about five months after being infected.

The VSV-based vaccine holds an advantage over recently described DNA vaccine approaches in that it does not require multiple injections. Rather, Rose reports, it can be given as nasal drops. "In the developing world and areas that have been hit hard with HIV and AIDS, it would be impractical and very expensive to inject millions of people with DNA vaccines," he observes. "The VSV-based vaccine would be a cost-effective and equally successful alternative to the other vaccines being tested. We are truly excited about this."