
                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: SUNDAY, May 29, 1994                   TAG: 9405290027
SECTION: NATIONAL/INTERNATIONAL                    PAGE: A3   EDITION: METRO 
SOURCE: Chicago Tribune
DATELINE: WASHINGTON                                LENGTH: Medium

5 INFECTED VOLUNTEERS PUT AIDS VACCINE STUDY IN PERIL

At least five volunteers in the government's principal AIDS vaccine study have become infected with the AIDS virus despite receiving the vaccine, raising concerns not only about how well the vaccine works but whether it may have increased the likelihood of their infection and - in one case - even accelerated the progression of disease.

Scientists in charge of the study say infections with HIV, the virus that most researchers believe plays a central role in AIDS, have been confirmed in two volunteers classified earlier as having a "low risk" for such infections, as well as three subjects whose lifestyles and sexual practices placed them in the group considered at high risk for AIDS.

One of the high-risk subjects, described as a woman whose sexual partner already was infected with HIV when she entered the study, and from whom she apparently later caught the virus, is said to since have undergone an unusually rapid decline in the number of white blood cells known as T-cells, the standard measure for the progress of AIDS.

None of the five cases has been reported so far in scientific literature. But they have been discussed at scientific meetings, including one closed-door session in Washington last month in which AIDS researchers from around the country met to debate whether the National Institutes of Health should go ahead with plans to test the vaccine on thousands of new, uninfected volunteers.

"We just don't know what we're going to do," said Dr. Jack Killen, the NIH official in charge of the vaccine trials, who acknowledged that the five post-vaccination infections had contributed to some researchers' doubts "that this is going to be a really good vaccine."

"The feeling is very mixed about the strength, duration and breadth of the immune response" demonstrated thus far by any of the candidate vaccines, Killen said.

"Nobody knows what we need for a successful immune response," he said.

Four of the five infections, Killen said, have occurred in volunteers given one of the two vaccines, made by the California companies Genentech and Biocene, that are under consideration for use in the expanded trials.

If those studies take place, they may include only 5,000 new volunteers rather than the 10,000 previously envisioned.

Both vaccines contain only a piece of the AIDS virus, called gp120, rather than the whole virus. Like other "subunit" vaccines that employ different pieces of the virus, the Genentech and Biocene products generate antibodies that, at least in theory, attack and neutralize the entire AIDS virus should it later appear.

The theory has been called into question, however, by the fact that each of the five vaccinated subjects who later became infected had previously developed normal levels of HIV antibodies.

"There was nothing unusual about the responses of these individuals. Nothing stands out about their response to the vaccine," Killen said.

Scientists do not understand why vaccine-induced antibodies, which represent a potent weapon against nearly every other known virus, apparently fail to neutralize the AIDS virus.

"These five people are going to be studied with more intensity than anybody else has ever been studied," said Dr. Barney Graham, a Vanderbilt University researcher involved in the vaccine trials.

by CNB