The data from last month’s much-hyped Thai AIDS vaccine trial are actually statistically insignificant, according to a secondary analysis published today in the New England Journal of Medicine. The original results from the trial, which included more than 16,000 people, concluded that the vaccine reduced infections by a statistically significant 31%. But the secondary analysis said it reduced infections only 26%, which could have happened by mere chance.
“The results are weak enough that we need to be very careful about assigning too much optimism to them,” said one UCLA immunologist. “It seems not so likely that the vaccine really did what it was intended to do.” The trial had combined two vaccines that had both proven ineffective previously. But one researcher said that the results could still be mined for information “of potentially great importance to the field.”