morning plenary:
Need for vaccine challenges
researchers to move quickly

30th June, 1998

While problems remain with the experimental vaccines currently in Phase I and II stage trials, Phase III trials should continue unhindered, said Hans Wigzell, a Swedish researcher who spoke at the 12^th World AIDS Conference’s first plenary session Monday morning.

"If we wait, we will never learn," Wigzell stated. "We have to go on."

Five to 10% of people at high risk for HIV appear to have special capacities to avoid infection, Wigzell noted, and cases of HIV-positive, long-term non-progressors have also been identified. Cases of natural immunity like these may provide clues for researchers attempting to develop a safe and effective vaccine against HIV.

However, barriers to such a vaccine include the existence of long-lived "silent cells" as well as the high variability among strains of the HIV virus. "Success in a functional vaccine will be measured by its ability to produce sterilising immunity, as well as a reduction in viral production."

Studies on macaques have shown that subunit vaccines need further development and that viral vectors or combination vector/subunits work better. Also, as we keep hearing, attenuated viruses, while more efficient, have serious safety issues. Wigzell said DNA vaccines represent the best hope so far, noting that none of the vaccines mentioned have progressed beyond early phase clinical trials.

"The upcoming Thailand Phase III trials are quite justified to perform," he stressed, referring to the VaxGen trial that has just begun. "Several different mini-trials should be begun, in specialised populations such as newborns and infected mothers. If we don’t begin now, we will have to wait decades."

these stories can also be found in The Bridge, the onsite print newspaper    

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