An experimental vaccine has helped monkeys with a form of the AIDS virus control the infection for more than a year, suggesting it may lead to a vaccine for people, US researchers have said.

The vaccine works by priming the immune system to quickly attack the HIV virus when it first enters the body, a point at which the virus is most vulnerable, US researchers said in a study published in the journal Nature on wednesday.

Doctor Louis Picker of the Oregon National Primate Research Center said he thinks it will be possible to have a vaccine ready to test in people within three years.

"We feel it has a possibility of keeping the virus under complete control or clearing the virus," Picker said.