STEPHEN KARPIAK Jr. born in Hartford, Connecticut died on this date. He graduated from the College of the Holy Cross with a degree in psychology in 1969 and earned his doctorate in experimental psychology at Fordham University in 1972. He joined Columbia University’s medical school as a researcher studying seizures and behavioral disorders.

In his 30s, Dr. Karpiak, living in the West Village, was immersed in the city’s gay nightlife. He partied until dawn at clubs like the Saint and the leather bar Ramrod, and he fell in love with a schoolteacher, who became his partner. When the AIDS crisis began, he started receiving messages on his answering machine from friends desperately seeking his medical advice. He also began attending funerals.

Dr. Karpiak left Columbia University in the mid-1990s and moved to Phoenix to run a clinic for people living with H.I.V. He also managed an agency there that provided housing for homeless men living with the virus.

He returned to New York in 1999 to lead the Pride Senior Network. One day, at a health fair, he gave out a simple questionnaire that asked: If you are older and were to suddenly fall ill, do you have someone who would care for you? After studying the responses, he undertook his research.

Dr. Karpiak joined the faculty of New York University’s College of Nursing in his 60s and later worked for G.M.H.C. (formerly Gay Men’s Health Crisis), where he founded its National Resource Center on H.I.V. and Aging. In 2010, Dr. Karpiak participated in a conference on H.I.V. and aging at the White House, and he helped start National H.I.V./AIDS and Aging Awareness Day.

When the coronavirus pandemic gripped New York, Dr. Karpiak grew concerned about how older people living with H.I.V. would be affected by lockdown. Sequestered in his Hell’s Kitchen apartment, he took part in web conferences with medical experts to address the topic. He always encouraged his research subjects to tune in, so that they could hear that someone was looking out for them.

When the coronavirus pandemic gripped New York, Dr. Karpiak grew concerned about how older people living with H.I.V. would be affected by lockdown. Sequestered in his Hell’s Kitchen apartment, he took part in web conferences with medical experts to address the topic. He always encouraged his research subjects to tune in, so that they could hear that someone was looking out for them.

“The Covid-19 pandemic showed us that we are an ageist society,” he said in 2020. “We hear misinformation constantly: ‘This virus only affects old people,’ so most people ‘don’t need to worry about it so much.’”

“I have heard many older adults say, ‘The worst thing in the world is to feel abandoned,’” he continued. “Even more unsettling is hearing from them, ‘There is something worse than AIDS, like loneliness.’”