While the jab was not able to stop the monkeys being infected in the first place, it strengthened their immune response to fight the virus.
If the results can be reproduced in humans, then it could be of particular benefit in countries where antiretroviral treatments are not widely available, as it could greatly reduce the chance of the infection being spread.
Their jab comprises a DNA vaccine designed to kick-start the body's immune system, with the addition of an extra immune system protein.
The protein is a chemical known to stimulate natural defence mechanisms in the body.
This was injected into Rhesus monkeys, who were then infected with a particularly vicious monkey version of the Aids virus.
Monkeys who were not given any vaccination were found to have large numbers of the virus, and badly damaged immune systems.
Approximately half had died within 140 days of being infected.
In contrast, the animals given the combined vaccine had much higher levels of immune system cells, and nearly undetectable levels of the virus in their bodies.
None developed any symptoms of Aids itself.
They fared better than monkeys given only the DNA vaccine - two of whom developed signs of full-blown Aids after 140 days.
Longer study
Now the team plans a follow-up study to see if the beneficial effects of the vaccine continue over a longer period.
Lead author Dr Dan Barouch said: "This potent, vaccine-elicited immune response can be capable of dramatically changing the clinical outcome of an Aids virus infection."
In the West, patients infected with HIV are frequently given cocktails of drugs designed to prolong their lives by both boosting their immune systems and keeping the quantity of virus in their bodies, or viral load, as low as possible.
It is thought that the lower the viral load, the less chance there is of the virus being passed on to another person - although there is still some risk.
However, these drugs are expensive, and beyond the reach of patients in many countries.
A simple vaccination, even one which has to be repeated at intervals, could reduce the transmission of the disease in these countries, as well as reduce the burden of Aids on medical systems.
A spokesman for HIV and Aids charity Terrence Higgins Trust Lighthouse hailed the results as "the first breakthrough of its kind".
However, he added: "It's important to note that this vaccine does not prevent infection with HIV and is not a cure.
"We must wait to see if trials in humans will replicate these results, and there is still a question over whether multiple vaccinations over a period of time will be necessary."