Usually monkeys infected with this virus will die within 2 years. Out of the 16 monkeys exposed to the virus, 9 of them cleared the virus and they were still clear of infection up to 3 years later.
It is still unclear why the vaccine only worked in some and not others, but researchers are postulating that it could be that SIV is so pathogenic that this is as good a result as you can expect. In the battle to beat the virus it seems that the vaccine won in about half of the case, whilst the virus won in the rest.
The vaccine is based on another virus , CMV ( Cytomegalovirus ), a member of the herpes virus family. It was modified so that it can’t cause infection and was used as it is very infectious and spreads quickly. This modified virus basically spurs the immune system on to fight the SIV. It then remains in the body and seeks out and destroys SIV indefinitely.
The vaccine is now being tested to see if it works at eradicating the virus from monkeys already infected, to potentially cure them.
Before this technique can be tried on humans safety trials will have to be done, but the hope is to start full human trials in the next 2 years. The hope is that it can lead to a therapeutic vaccine that can clear the infection in humans
Exiting news. Watch this space!