A case for the books
The world just learned that a Mississippi child born HIV-positive is, now 2.5-years-old, functionally cured of the infection. This hasn't verifiably happened before. Harvard surgeon Atul Gawande tweeted that it was "world-changing." Potentially, yes, in that around 300,000 infants are born infected with HIV every year (though only about 100 in the U.S.). Dr. Yvonne Bryson, chief of global pediatric infectious disease at UCLA told the New York Times it's "one of the most exciting things I've heard in a long time.'' Her more staid assessment is best.
Infant HIV infection can occur during pregnancy, during delivery, or during breastfeeding. But, especially in the U.S. and other resource-rich places, we've already come a long way in preventing it. If an HIV-positive mother is taking antiretroviral medications during her pregnancy, the risk of transmission to her fetus is less than 2 percent. Good odds, but not good enough. So infants born to HIV-positive mothers are also given zidovudine, right away, which is considered a prophylactic measure. They typically take it for their first six weeks of their life, even if they never test positive for HIV. That's been found to lower the odds of transmission another 66 percent. But we don't have good studies on giving infants all-out antiretroviral treatments, which can be toxic, until after we get results from blood tests that indicate they've definitely been infected.
In this case, though, Dr. Hannah Gay, who was caring for the infant, "immediately used a three-drug regimen aimed at treatment, not prophylaxis, not even waiting for the test results confirming infection." Some doctors will do that, as a judgment call, if the odds of infection are high. By the time the tests did come back, they were positive -- and reportedly replicated and verified five times.
When the baby was 18 months old, though, her mother stopped bringing her to the doctor, and stopped giving her the medications. Which created a second dimension to this scenario that experiments will struggle to replicate, ethically. We would expect the virus to return to higher levels, but they didn't. One year later, the child still has no detectable HIV.
While the story does offer hope that we can replicate this result, one case is one case. Either way, great for this kid, and a day that should live in history and inspire progress.