Vaccine protects monkeys against SIV
A vaccine has been developed that protects monkeys from Simian Immunodeficiency Virus (SIV), the monkey equivalent of HIV. This breakthrough could eventually lead to a vaccine for humans, protecting them from HIV.
After more than 12 months, the majority of monkeys vaccinated against one type of SIV were more or less disease free. The vaccine did not prove effective against another strain of SIV. Unvaccinated monkeys went on to develop the monkey equivalent of AIDS during the trial period.
The vaccine was novel in that it contained SIV material (for triggering an immune-response) wrapped in a cytomegalovirus (CMV) - the virus that causes herpes in humans.
The researchers chose CMV because most humans are already infected with it and the virus stays in the body for life. The vaccine virus became established in the monkeys so the monkey immune system was continuously being stimulated by SIV antigens to defend itself.
Previous vaccination attempts have used the flu virus as a vector to bring SIV material into the host but these have proved ineffective.
The next step in vaccine development is to test the vaccine in clinical trials in humans. For a human vaccine the CMV vector would be weakened sufficiently so that it does not cause illness, but will still protect against HIV.