The long, discouraging, and expensive struggle to find an AIDS vaccine has hit a major road block, and scientists are left confused as to what went wrong and where to go from here. Two field tests for the "most promising contender" out of the possible AIDS vaccines, "made from a common respiratory virus called adenovirus type 5 that had been crippled and then loaded with fragments of HIV," have been halted after it was discovered in one of the field tests that the vaccine not only didn't prevent the virus but may have also increased the risk of contracting it.

That National Institutes of Health are meeting next week to figure out where to go from here with the AIDS vaccine program. But scientists are saying the prognosis is grim.

"None of the products currently in the pipeline has any reasonable chance of being effective in field trials," Ronald C. Desrosiers, a molecular geneticist at Harvard University, declared last month at an AIDS conference in Boston. "We simply do not know at the present time how to design a vaccine that will be effective against HIV."

If you're waiting for the good news, there wasn't much of any in this story, sadly. [WP]