Plans for large scale tests on an experimental AIDS vaccine were cancelled by the U.S. National Institutes of Health, due to concerns about its safety, 10 months after trials on a similar vaccine failed. Dr. Anthony Fauci, director of the National Institute for Allergy and Infectious Diseases said, though the decision was his alone it followed months of meetings to discuss the options of proceeding or stopping. Concern about the similarities between the two vaccines and Merck’s vaccine having showed increased susceptibility to the disease for those who received it, were a major concern.  

The proposed $160 million test of the NIH vaccine was to be known as PAVE 100 was first delayed and then scaled down, just months away from launching its study with 8,500 volunteers, due to the trial failure of the similar vaccine from Merck & Co. Both the vaccines could not prevent HIV but were designed to stir up an immune response that could keep infections in control in mimicry of the natural control of the virus that a few people appear to have.

For the people advocating the use of the vaccine, Dr. Fauci’s decision came as a surprise. "We supported the scientific premise of the trial and believed that it was being designed in such a way that participants' safety would be protected to the fullest extent possible," said Mitchell Warren, executive director of the AIDS Vaccine Advocacy Coalition in New York.

The vaccine had people hopeful for a cure from AIDS, a deadly disease that affects 33 million people. "After a year of public hand-wringing and unproductive public attacks on the search for an AIDS vaccine, it is essential this decision not be viewed as a vote of no-confidence," said Mitchell Warren, executive director of the AIDS Vaccine Advocacy Coalition in New York.

Dr Fauci is looking into proposals that are smaller in budget and size with modest goals to the original plan. "We're not going away," Dr. Fauci said. "I don't see this as chilling, but realistic."