The trials were not scheduled to start until later this year, but GeoVax said it was launching them earlier due to positive results from previous studies.

The trials will involve the company's DNA and MVA vaccines that are intended to prevent infection with the HIV-1 strain of the virus. One trial will look at administering few vaccine doses, while the other trial will utilize only the MVA vaccine.

"The excellent vaccine safety profile demonstrated (in previous trials) was key to accelerating the start date of these new human trials," said Don Hildebrand, GeoVax's chief executive officer, president and co-founder. "Equally important are the positive immune responses observed in people receiving only 1/10th of a dose of our vaccines. This is very encouraging news."