NEW YORK — Hunein Maassab witnessed a transformational moment in public health when he was a young doctoral student at the University of Michigan. It happened on April 12, 1955, the day his mentor, Dr. Thomas Francis Jr., announced that he had completed a vast field trial involving nearly 2 million children to determine the effectiveness of what at the time seemed like a miracle drug: a vaccine for polio.
The vaccine had been developed by one of Francis’ former lab researchers, Jonas Salk, and Dr. Maassab had worked on the field trial, studying blood samples. Listening as Francis, a renowned virologist who had developed some of the first flu vaccines, described the study in a campus auditorium, Dr. Maassab knew the direction he wanted his life to take.
“That was his initial inspiration, that he wanted to develop something like that for humankind,” Rashid L. Bashshur, a close friend, said. “That would make his life worthwhile.”
Nearly half a century later, in June 2003 — after decades of starts and stops, of tinkering and test trials, of government reviews, patent applications, and corporate twists — Dr. Maassab’s work came to fruition when the Food and Drug Administration declared a nasal-spray flu vaccine he had developed safe for healthy people ages 5 to 49 who are not pregnant. It carried the brand name FluMist.
Not long afterward, the vaccine was approved for children as young as 2. It is now commonly administered, with many people choosing it over an injection.
Dr. Maassab, who was born in Syria and began using John as a first name after he moved to the United States in the late 1940s, was 87 when he died on Feb. 1 in North Carolina.
Unlike previous flu vaccines, Dr. Maassab’s spray used a live version of the influenza virus that had been attenuated, or weakened, so as not to cause the flu. He also adapted the vaccine so that it activates quickly upon entering the body in the relatively cool region of the nasal passages. Getting it right, and getting it approved, took a long, long time.
As early as 1960 he had isolated a strain of flu virus for developing a vaccine. By 1967, he had written about his work in the journal Nature. Over the next three decades, working with several colleagues, particularly Brian R. Murphy at the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, he completed the hard work of science — developing dozens of live attenuated viruses, documenting the genetic makeup of certain flu viruses, developing ways of quickly adjusting vaccines to the variants of the flu that emerge each year.
More than 70 studies and trials were conducted, covering more than 9,000 volunteers. By the late 1990s, tests showed that the vaccine successfully prevented the flu 85 percent of the time, a better rate than that for the injected, nonliving vaccine. (Tests since then have shown the nasal spray to be even more effective.)
“I feel in a sense that I have accomplished my life’s dream,” Dr. Maassab, who had retired, said after FluMist was finally approved. “I spent all my lifetime developing this vaccine.”
Dr. Maassab was born in Damascus. He enrolled at the University of Missouri, where he received a bachelor’s degree in biology in 1950 and a master’s in physiology and pharmacology in 1952. He then moved to Michigan, where he earned a master’s degree in public health in 1954 and his doctorate in epidemiology in 1956.