Fallout From Failed AIDS Vaccine Could Dampen Research

By E.J. Mundell
HealthDay Reporter
Tuesday, November 13, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

MONDAY, Nov. 12 (HealthDay News) -- An experimental AIDS vaccine used in a recent trial may have placed participants at higher risk of infection with HIV -- although whether or not that was truly the case remains unclear.

What is clear is the concern among experts that the news will keep would-be trial participants away from future AIDS vaccine studies.

"That's always a possibility, and that's the reason why we have to be very transparent and open and honest, and be very energetic to educate people to understand just what went on here," said Dr. Anthony Fauci, an AIDS research pioneer and director of the U.S. National Institute of Allergy and Infectious Diseases (NIAID). The institute was a partner in the trial.

"Already we have a lot of people misinterpreting that the vaccine itself actually gave [recipients] HIV infection -- that's impossible," he said. "We have a lot of education to do, and there's always a danger that this could sour people on getting involved in vaccine trials."

Another expert agreed that the collapse of the large, phase II trial of Merck & Co.'s V520 vaccine could send the wrong message.

"It's a blow to the HIV prevention field," said Rowena Johnston, vice president of research at the Foundation for AIDS Research (amfAR) in New York City. "Clearly, we want to be very careful that people aren't thinking that AIDS researchers are going to be putting them at risk."

The V520 vaccine was the first of the so-called "viral vector" HIV vaccines to make it all the way to such a large, phase II trial, after showing much promise in smaller, earlier studies.

The vaccine used a harmless adenovirus -- a type of cold virus -- as a "vector" to deliver a set of three synthetically derived HIV genes. The hope was those genes would help prime the immune system against the virus that causes AIDS.

The virus vector approach is a common one in vaccine research generally, and HIV/AIDS experts had high hopes for the Merck vaccine, which was meant to be tested in more than 3,000 volunteers uninfected with HIV.