Meanwhile, the canarypox vaccine may work better to spur the production of the HIV-fighters in volume.

FORBES: Merck, Aventis Team On AIDS Vaccine

Merck's adenovirus and Aventis' canarypox seem to infect different kinds of immune cells.

FORBES: Merck, Aventis Team On AIDS Vaccine

Aventis, a Franco-German pharmaceutical firm, is using canarypox virus to do just that.

ECONOMIST: AIDS vaccines on trial | The

Aventis picked canarypox, a bird virus that doesn't affect people.

FORBES: Magazine Article

Merck and Aventis will immediately start giving booster shots based on Aventis' current version of the canarypox vaccine to 90 or more patients who have already participated in a test of Merck's adenovirus vaccine.

FORBES: Merck, Aventis Team On AIDS Vaccine