In June 1981, a curious report appeared in the Center for Disease Control’s weekly public health digest: Five young, gay men across Los Angeles had been diagnosed with an unusual lung infection known as Pneumocystis carinii pneumonia (PCP) — and two of them had died. It was the first time that acquired immunodeficiency syndrome (AIDS) — the devastating advanced-stage of HIV infection that would go on to claim the lives of more than 32 million people globally — was reported in the US.