A man who likely contracted HIV only 10 days before starting Truvada (tenofovir disoproxil fumarate/emtri-citabine) as pre-expo-sure prophylaxis was ultimately put on a full HIV treatment regimen after a week of PrEP use. (It took that long to properly diagnose such a recent infection.) After three years of treatment, he stopped taking antiretrovirals (ARVs) and then went seven months before his viral load rebounded. Ultrasensitive tests conducted while he was on treatment showed a near-total or total loss of any detectable virus. Scientists have much to learn from these rare cases of so-called viral remission. In particular, they are investigating how the apparent size of an individual’s reservoir—the infected cells that evade standard ARV treatment—may help predict the length of such a viral remission.