Stephen Karpiak, Pathbreaking H.I.V. Researcher, Dies at 74

“Losing all those people was never far from his mind,” said his brother, who is his only immediate survivor. “And it tied deeply into his personal life. He lost his lover, who was his soul mate.”

His partner’s death stirred something in him.

“When he finally saw those who survived, he saw they weren’t surviving well,” he added. “So Stephen thought, ‘How can I do something about this?’ He couldn’t do anything when it was happening in the 1980s, but then he got his chance.”

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.

Dr. Karpiak 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.

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 they could hear that someone was looking out for them.

“The Covid-19 pandemic showed us that we are an ageist society,” Dr. Karpiak 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.’”