Can the AIDS Pandemic be Curtailed Through the Use of Current HIV Vaccines and Highly Active Antiviral Therapies?

SJUN 10 '97 11:48AM AAAS SCIENCE MAGAZINE JUN. 3. 1997 12:2/5 P 2
WOM: Mu ins Lab - Uw PHONE NO.: 2866161850
Muilins. Page 1
Can the AIDS pandemic be curtailed through the use of current HIV vaccines and
highly active antiviral therapies?
Sir & Madam: The decision not to go forward with phase 3 efficacy trials of human U
immunodeficiency virus type I (WV-1) vaccines in the U.S. In 1995 was based in part on.
the paucity of data suggesting that current vaccine candidates would provide sterilizingm
immunity, as well as our poor understanding of the immune correlates of protection.
We are arguably not now much closer to having either requirement satisfied.
Furthermore, trials of SIV vaccine candidates have generally been disappointing
because despite eliciting a range of antiviral immune responses, persistent infection
usually results from virus challense. Three recent findings, however, provide a logical
basis for cautiously moving toward phase I trials without satisfying the above
requirements.
First, virus load in vaccinated and subsequently simian immunodeficiency virus
(SIV) infected macaques, when measured, has consistently been reduced relative to
unvaccinated controls (1, 2, 3, 4, 5, 6). Second, a strong correlation has been established
between low MV-I plasma virus load and long term survival in humans (7). Third,
studies of perinatal transmission of WIV-1, the only form of transmission for which
suitable data is available, have shown that low virus load is associated with a reduced
probability of virus transmission (8, 9, 10, 11). Hence, if HIV-i vaccines fail to prevent
infection but do succeed in reducing virus load for extended periods in subsequent
human infections, then vaccinees, though they may still get infected, may have a more

protracted period of asymptomatic infection. Indeed, preliminary observations of
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