Positive Results for HIV Vaccine in Monkeys

A new vaccine of Simian Immunodeficiency Virus (SIV), the version of HIV that exists in monkeys, has proven to be effective in about half of its test subjects who were exposed to the virus later in life, according to a new study published in the journal Nature.

Louis Picker, M.D. (pictured) of the Oregon Health Sciences University, made the breakthrough after a decade of research in developing an HIV vaccine.

The researchers tested their vaccine in rhesus macaque monkeys at the Oregon National Primate Research Center, according to the university. Of the monkeys who were vaccinated, more than half were found to be uninfected by SIV and, after eight years, most of the monkeys were able to maintain control of the virus. However, the unvaccinated animals who were exposed to the virus have developed the monkey form of AIDS.

The vehicle for introducing the vaccine to the body is the cytomegalovirus, because it is believed that most people are already infected with it even though it causes few or no symptoms. Once a person is exposed to the cytomegalovirus, it inhabits their body for life. The theory was that because the CMV can remain in the body for life, it could contain the HIV vaccine while causing minimal complications. From there, it would build and maintain a resistance against HIV by programming effector memory T-cells, part of the immune system, to be constantly on the alert for the virus.

While in humans, antiretroviral therapy can control the virus, it cannot rid the body of the virus, which hides within the immune systems of its own cells. Picker told the Portland Tribune that the results could lead to testing for the vaccine in humans, but it would take years before that could begin.