It’s the news that the HIV community has been waiting four long decades for: the hint that maybe, just maybe, HIV can be cured.

Dr. Xu Yu, a principal investigator at the Ragon Institute of Massachusetts General Hospital, MIT and Harvard, as well as an associate professor of medicine at Harvard Medical School, had to check and recheck her results to be sure. In one of her patients, test after test to detect evidence of HIV in the woman's blood came up empty.