AIDS treatments are improving, but no cure is likely in this decade, David D. Ho told a New York audience after accepting a newly created prize for medical research. Ho, director and chief executive officer of the Aaron Diamond AIDS Research Center at Rockefeller University, received the Lewis and Jack Rudin New York Prize for Medical Research on Thursday (October 30) at the New York Academy of Medicine and delivered a lecture titled, HIV in 2010: What Will the Science Allow?

It was a theme he took on reluctantly, he said, given the difficulty of making predictions. The prize awarded to Ho was in recognition of his research on subjects including antiretroviral therapies, which have dramatically extended lifespans for AIDS patients by limiting viral multiplication.

Barring major new findings, Ho said, "I do not see us going from being able to control viral replication to a cure." But he added that current therapies could improve through lower toxicity, more potency, simpler regimens, and new drug targets. A key challenge is to make antiretrovirals cheaper for people in developing nations, he said.

Ho said that several potential AIDS vaccines are under investigation. But in a research field littered with past disappointments, he took care not to raise hopes.

Ho blamed the difficulty in designing a vaccine on the rapid mutation rate of the virus, its protective outer coating, and its ability to "hide" for long periods in the immune system's memory cells.

Nonetheless, the Diamond center plans to begin phase I clinical trials this month on a vaccine strategy consisting of an initial shot of plasmids containing HIV genes and a booster shot of a modified smallpox virus containing the same genes.

Researchers have several reasons to hope this strategy might work, Sarah J. Schlesinger, a research scientist at the center, told The Scientist: The vaccine uses five HIV genes rather than one, the more usual approach; the developers have ensured particularly robust expression of the proteins the genes encode; and the two-shot strategy exploits different immunogenicity targets, the major histocompatibility complex class I and class II processing pathways.

In a recent review article, Norman L. Letvin, professor of medicine at Harvard Medical School, wrote that recent animal studies suggest partially effective AIDS vaccines may be within reach: "The conviction is growing that an HIV vaccine that at least slows disease progression, if not one that prevents infection, is possible."