The encouraging news about AIDS, notably the "cocktail" drugs that are keeping patients alive for years, is running up against the discouraging cost of the drugs and their possible side effects. So the incentive for developing a vaccine against the epidemic remains strong. That is the starting point for tonight's careful inquiry on "Nova" into new approaches that seem to hold out some promise of success.
As "Surviving Aids" explains early on, the special problem about AIDS lies in the nature of H.I.V., a retrovirus that may linger in cells for years as it destroy's the body's immune system. Scientists fear that introducing even a small nontoxic dose as a vaccine may prove to be a killer.
Tonight's glimmers of hope come from major research centers like Massachusetts General Hospital, the Aaron Diamond Aids Center in New York and the National Cancer Institute, where volunteer patients have produced surprises about the apparent workings of their immune systems.
Consider Bill Massie, whose blood was found to contain antibodies against H.I.V., proof that he was infected; yet there was no trace of an active virus. The question is whether and how his immune system was holding H.I.V. in check. The answer points to the workings of two sets of white blood cells, "CD4 helper T cells" and "CD8 killer T cells." Don't be put off by the mysterious labels. You'll have to watch the program to get the intricate details, but the theory is that the killer cells, usually helpless against H.I.V., are for some still undetermined reason doing their job for Mr. Massie.
The narrator sums up: "Massie was breaking all the accepted rules of H.I.V. infection. His natural immune defenses were keeping the virus under control." And he is opening up an entirely new approach to understanding the virus.
In New York, researchers have come upon another man, Steve Crohn, who has remained uninfected despite repeated exposure to H.I.V., and through him they are learning more about genes and the way H.I.V. works or fails to work. Count on the good old "Nova" animation to clarify matters for viewers.
Other cases are explored, particularly the early and aggressive use of cocktail drugs in hopes that they may turn out to produce immunity. In one risky experiment, a patient has been taken off his 14 pills a day to test whether his immune system will kick in and control the virus. No definite conclusion yet.
Wherever the research may lead, "Surviving AIDS" offers an intriguing look at current laboratory thinking as scientists follow up on clues that may lead to making the program's title a reality for many more patients.
(Channel 13, New York, at 8)
Written, produced and directed by Elizabeth Arledge; Paula S. Apsell, executive producer; Lakshmi Govind, associate producer. A Nova production by Ms. Arledge for WGBH/Boston.