On Thursday, federal researchers gave up on their plans to carry out the large scale experimental testing of an AIDS vaccine the National Institutes of Health had developed. A similar attempt was recorded last September from drug maker Merck & Co.; the results however were not as good as company officials expected: several volunteers were left with increased vulnerability to HIV infection.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, took full responsibility for the decision, adding however that it took several months of debates to reach this resolution.

Once the results of the Merck vaccine were out, Anthony Fauci initially delayed his project and then scaled down the sum of $160 million that was supposed to go into the testing of his NIH vaccine. As PAVE, the Partnership for AIDS Vaccine Evaluation, had a very similar approach to that attempted by Merck, government researchers have been trying to figure out the reasons for its failure, in order to perfect their own product.

The Merck vaccine was the first and most promising out of a newly-developed class of HIV vaccines that had been approved for human testing. It was developed from a version of the common cold virus (adenovirus type 5), which helped with the delivery of three synthetically produced genes (gag, pol and nef) of the AIDS virus.

Dr. Alan Bernstein, Global HIV Vaccine Enterprise executive director, fully supports Dr. Fauci’s decision and considers that currently, there is an "urgent need for a diversity of new approaches to H.I.V. vaccine design."