Dr. H. Fred Clark, PhD '67

Long time coming

When H Fred Clark (PhD, ’67) received the rarely awarded Gold Medal of The Children’s Hospital of Philadelphia, he was no overnight sensation.  Clark was honored for his work as one of the inventors of a vaccine to prevent rotavirus gastroenteritis, a common childhood illness that’s the largest infectious-disease killer of infants and young children worldwide.  That achievement came as a result of nearly 30 years of research in rotavirus and half a century of work in virology.  

Clark has made his career in viral pathogenesis, that is, how viruses cause disease in people.  Though he graduated from Cornell with a doctor of veterinary medicine degree, prior interest and an intern experience in human disease research led him to obtain his doctorate at UB in microbiology and immunology.  That degree, he says, was a “great advantage.  People tended to be physicians or vets or become basic researchers.  I was able to integrate my studies of biochemistry, immunology and animals.”

Research begins at UB

For several years after leaving UB, Clark did research in a range of diseases, both human and animal—leprosy, tuberculosis, Rocky Mountain spotted fever, rabies, hepatitis-B.  In the late ‘70s, he joined the research staff of The Children’s Hospital of Philadelphia and switched his studies to the rotavirus, which had been discovered in Australia in 1973.  Rotavirus causes severe infant diarrhea and, says Clark, “kills about 600,000 babies a year worldwide.  It causes about 70,000 hospitalizations in the U.S.”  At the time, no treatment existed except keeping the sufferer hydrated.  With a disease of such prevalence, finding a vaccine became an obvious goal

The National Institutes of Health and Wyeth Lederle first licensed a rotavirus vaccine in the US in 1989, but it was voluntarily removed from the market because it was found to be associated with a severe side effect—a condition where the bowel twists on itself.  Clark was working with the pharmaceutical company Merck & Co., Inc., at the time on the development of another rotavirus vaccine. Merck conducted global studies involving more than 70,000 babies to ensure that the vaccine Clark's team developed was safe.  Ultimately, after nearly 27 years and  significant development costs , the US Food and Drug Administration licensed this vaccine—RotaTeq®-- in February 2006. RotaTeq has subsequently been licensed in many countries worldwide.

The benefits of a vaccine against rotavirus are obvious.  In addition to saving thousands of children’s lives, says Clark, “It should also greatly reduce the burden on pediatric hospitals and departments.  Doctors are very enthusiastic to get rid of the disease.”

Minor "bumps" 

With 27 years of work on the vaccine, Clark obviously encountered, as he terms them, “bumps” along the way.  One of the toughest was growing human rotaviruses for study.  Clark’s charge was making hybrid viruses and testing them in vaccine candidates.  “There are five major types of human rotaviruses,” he says, “and we had to make reassortments of those.  We made them with bovine viruses.  That was a big job.  Lots of those didn’t work, but we finally found five that did.”

Today, Clark and his team are monitoring the change in vaccine strains; different strains become important in different years, he explains and “we have to figure out why.”  The team is also trying to gauge the success of the vaccine under real-life conditions.  “That will take us a few years,” Clark says.

Clark stresses that the commitment of the project’s sponsor, Merck & Co., Inc., “was incredible in terms of the amount of risk taking.  The figure that’s thrown around is that 1 out of 250 drugs actually make it to production from development.”  He also cites a “certain amount of serendipity and good luck.  But you decrease the element of luck when you have lots of smart people working together, including the team assisting me at Children’s and several hundred people at Merck.”  Though Clark has worked in virology for 50 years, he considers RotaTeq® the most important accomplishment of his life.

Written by Grace Lazzara
July 2007

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