Because the early cases appeared in the gay community, the new disease was first called "gay-related immunodeficiency disease" (GRID). Many scientists and public health officials initially hypothesized that behavioral elements of the homosexual lifestyle (multiple sex partners, for example) were the cause. Another early theory was that "poppers" (amyl nitrates), drugs frequently used by some gay men to enhance sexual pleasure, were the cause (CDC, MMWR, June 18, 1982).
In June 1982, the CDC reported 355 cases of opportunistic infections, with an increase in the number of heterosexual patients, particularly among IV drug users. According to the report, "a laboratory and interview study of the heterosexual patients [was] in progress to determine whether their cellular immune function, results of virologic studies, medical history, sexual practices, drug use, and lifestyle [were] similar to those of homosexual patients" (CDC, MMWR, June 11, 1982). One month later, the CDC reported 34 cases of opportunistic infections in Haitian patients. The pattern of infections was "similar to the pattern recently described among homosexual males and IV drug users" (CDC, MMWR, July 9, 1982).
On July 16, 1982, the CDC reported the first three cases of PCP among individuals with hemophilia. All three were reported to be heterosexual males. At this time, the CDC postulated that the immune dysfunction symptoms were transmitted through blood and blood products:
The clinical and immunologic features these three patients share are strikingly similar to those recently observed among certain individuals from the following groups: homosexual males, heterosexual IV drug users, and Haitians. Although the cause of the severe immune dysfunction is unknown, the occurrence among the three hemophiliac cases suggests the possible transmission of an agent through blood products [CDC, MMWR, July 16, 1982].
On the same date, the FDA's Bureau of Biologics convened a meeting to discuss opportunistic infections in hemophiliacs. The meeting included representatives from the CDC, the National Hemophilia Foundation (NHF), the American Red Cross, the American Blood Resources Association (ABRA) (who represented the plasma fractionators), and the National Institutes of Health (NIH). The CDC presented an update of the epidemic of opportunistic infections, noting that the one common thread among all groups affected (i.e., homosexual men, IV drug users, Haitians, and individuals with hemophilia) was the presence of markers for hepatitis in more than 90 percent of each group (Hansen 1982).