Three decades ago, the June 5, 1981, issue of Morbidity and Mortality Weekly Report (MMWR) reported on five previously healthy young gay men in Los Angeles diagnosed with pneumocystis carinii pneumonia (PCP), an infectious disease usually seen only in people with profoundly impaired immune function. As a specialist in infectious diseases and immunology, I had cared for several people with PCP whose immune systems had been weakened by cancer chemotherapy. I was puzzled about why otherwise healthy young men would acquire this infection. And why gay men? I was concerned, but mentally filed away the report as a curiosity.
One month later, the MMWR wrote about 26 cases in previously healthy gay men from Los Angeles, San Francisco and New York, who had developed PCP as well as an unusual form of cancer called Kaposi’s sarcoma. Their immune systems were severely compromised. This mysterious syndrome was acting like an infectious disease that probably was sexually transmitted. My colleagues and I never had seen anything like it. The idea that we could be dealing with a brand-new infectious microbe seemed like something for science fiction movies.