Cladd Elizabeth Stevens M.D., M.P.H

Cladd Elizabeth Stevens, M.D., M.P.H., a medical researcher whose work at the New York Blood Center helped establish the safety and efficacy of the hepatitis B vaccine and opened early lines of inquiry into AIDS at U.S. blood centers, died on September 10, 2025, in Marietta, Georgia. She was 84.

Dr. Stevens joined the New York Blood Center Lindsley F. Kimball Research Institute in the 1970s and in 1981 became head of its Laboratory of Epidemiology. The following year, she launched an AIDS research project at the center as the epidemic began to reshape blood safety and public health.

With colleagues, she helped design and conduct a series of placebo-controlled, randomized, double-blind trials that changed vaccine practice: the 1980 New England Journal of Medicine trial among 1,083 men in New York, follow-up studies in dialysis-unit staff and hemodialysis patients, and later work demonstrating the effectiveness of yeast-recombinant hepatitis B vaccine. Those studies provided the evidence base for protecting high-risk groups and, ultimately, the wider public.

In later years, Dr. Stevens co-authored reviews on preventing mother-to-child transmission of hepatitis B, with collaborations that included the CDC’s Division of Viral Hepatitis in Atlanta. She served as a consultant for the New York Blood Center National Cord Blood Program and for the Memorial Sloan Kettering Cancer Center Adult Bone Marrow Transplant Service.

She earned her medical degree at Baylor University College of Medicine in Houston, Texas, a master’s in public health at the University of Washington School of Public Health and Community Medicine in Seattle, and completed early research training in Taiwan before settling in New York. She earned a BA in pre-medicine at Pomona College in Claremont, California, where she met many of her closest lifelong friends.

In 2011, she married Dr. Ronald James Prineas, and they resided in New York’s Upper East Side where they welcomed and entertained friends and relatives from across the United States and Canada. Her curiosity, generosity, and sense of humor were a source of delight to those who knew her, and her laughter could light up any room.

Dr. Stevens found joy in ceramics—as a maker, a student of form, and a museum-goer—an interest she carried with her from New York to her most recent home in Marietta, Georgia. She also loved baseball and was a lifelong Yankees fan. Besides ceramics, she enjoyed the New York Yankees, plants and gardens, and international travel.

She is survived by her husband, Dr. Ronald James Prineas, and his children, Matthew, Anna, John, and Miranda, and their spouses and children. She is also lovingly remembered by her niece Melissa Delaney and her husband Jack, along with their children Kevin, Jeanette, Ethan, and John; and niece Susan Lummis and her husband Jeff, as well as their children Kristi and Stephanie, and grandchildren who brought her joy as grand nieces and nephews. She is lovingly remembered by her nephew, Mark Stevens, and his wife Sandra, along with their children, Christopher and his wife Shana, and Brittany; her nephew Isaac Stevens, his wife Amanda, as well as their children Lizzie and Graham; her step-niece Susan Waschevski, her son Rigby, and step-nephew Michael Waschevski; and her sister-in-law Sharyl Stevens.

Cladd’s legacy lives on not only in her scientific contributions but in the deep love she shared with her family and friends. Her warmth, laughter, and steadfast presence will remain with them always.

A memorial will be held on September 18, 2025, from 5–7 pm at Roswell Funeral Home, 950 Mansell Road, Roswell, Georgia.

In lieu of flowers, the family invites contributions in her name to AMOCA, the American Museum of Ceramic Art, which Cladd loved and took special pride in because she served on the board there and was close friends with Pomona College classmates David (’62) and Julie (’63) Armstrong.