Robert G. Sharrar

Robert G. Sharrar, MD, has been a Fellow of The College of Physicians of Philadelphia since 1976. That year, he led the communicable disease division at the Philadelphia Department of Public Health, and was involved in what was at the time the biggest epidemiological investigation undertaken by the Centers for Disease Control and Prevention (CDC). After a gathering of members of the Pennsylvania chapter of the American Legion in Philadelphia over Independence Day weekend, several Legionnaires became ill with a flu-like illness when they returned home. Over the following weeks, the epidemiological and bacteriological investigation would uncover a brand new organism. As Dr. Sharrar put it, “a bacteria that loves the lungs of Legionnaries,” Legionella pneumophila. 

On May 1, Dr. Sharrar sat down for an interview with Dr. René Najera, Director of Public Health of The College of Physicians of Philadelphia. Joining them were Alavi Hossain from Thomas Jefferson University, LaBreshia Taylor from Arcadia University, and Masha Morozov from the University of Pennsylvania Perelman School of Medicine. All three are public health students chosen from the recent Student Public Health Poster Session held at the College on April 24, 2023. Among the topics discussed were Dr. Sharrar’s interest in medicine and public health, his experiences during the Legionnaires’ Disease epidemic, during the arrival and establishment of the HIV/AIDS pandemic, and his time working for Merck. 

Alavi Hossain: How did you know that medicine was your calling? 

Dr. Sharrar: “I fortunately have an identical twin brother. And he was always interested in medicine. When we both went to Franklin Marshall College, he studied medicine. And I basically did a general curriculum and decided to major in chemistry. But I realized that I didn't really want to spend my life in the laboratory. So I switched to medicine also, and we both ended up going to medical school at the same time. He's currently a pediatrician while I did my major in internal medicine and infectious diseases.” 

LaBreshia Taylor: How did you shift from medicine to public health? 

Dr. Sharrar: “I was lucky enough to spend a summer in what was then called West Pakistan working in a mission hospital. And I got to know a lot about many of the public health issues at the time. Also, when I came back to Penn to finish my medical training, I applied to the public health service for work. Because back then, we all either had to go to the military or do public health work. And it's interesting, while I was in Pakistan, I met a guy named Mike Gregg, who was there doing research with the University of Maryland Research Center in . And he ended up being at the CDC. And he invited me to join the epidemic intelligence service when I was doing an internship. So I jumped at it. I did not know a whole lot about it at the time, but I was accepted into the EIS program. And so I went down to Atlanta at the CDC. And Dr. Alex Langmuir, who was the head of the epidemiology program, began the course by teaching us all epidemiology.” 

Through the Epidemic Intelligence Service (EIS), Dr. Sharrar learned to care for a population, not just individuals, as most physicians do. From his time with the EIS, Dr. Sharrar then landed a job at the Department of Public Health in Philadelphia. 

Masha Morozov: Can you tell us about your experience with the Legionnaires’ disease epidemic of 1976? 

Dr. Sharrar: “Well, it was a very interesting and unique experience. And it's interesting how it happened. [In] 1976, they had the American Legion Convention in Philadelphia. The people were at the convention and they went home. And so people actually started getting sick when they were home. And we didn't know about it in Philadelphia. Pneumonia isn't a reportable disease, as per se. I first learned about it when I went into my office on Monday morning, August the 4th. In fact, I think because of the news media coverage we really did learn about every case of Legionnaires disease that occurred in Philadelphia. We invited the CDC to come up to help us investigate it because we really didn't have the resources to do it by ourselves. I was only the only epidemiologist in the city at the time. And David Frazier, who was at the CDC's at the time, actually led the investigation.” 

Dr. Sharrar explained how about 25 EIS officers were sent by CDC, and they did epidemiological investigations throughout the Commonwealth of Pennsylvania, “collecting data about the cases that were occurring.” All those data were compiled and analyzed, and a better picture of what happened was put together: “We were able to look at the distribution of cases, using the epidemiologic variables of person, place, and time. We learned a couple of things about it. First of all, the epidemic began occurring about eight to ten days after the convention, after people went home... So, by the time we found out about it, most of the cases had already occurred.” The investigation also showed that cases were exclusive to those who attended the conference. “People who were in Broad Street in front of the hotel” were also falling ill. 

Dr. Sharrar then said that nothing was growing in the environmental samples taken at the hotel, and the number of cases declined. “And so, at the end of August, the CDC packed up and went home, and we kind of didn't know what else to do. We kept monitoring in Philadelphia just to see if anything came up. But nothing came up.” There would be a breakthrough at CDC laboratories later that year. “Then around Christmas time, a guy named McDade who worked in the lab at the CDC began reviewing some of his data. And because he thought he had seen some contamination occurring when he did the analysis earlier. And we went back and did the analysis again. The contamination was still there. And so they then studied it, and they were shown that it was what they described as a pleomorphic gram negative organism.” The organism would be named Legionella pneumophila, after the Legionnaires infected and killed. 

Alavi Hossain: Can you tell us about your experiences in Philadelphia when HIV/AIDS arrived? 

Dr. Sharrar remembered reading the first reports of cases of opportunistic infections in immune-compromised patients. He had treated similar cases in Philadelphia, but made nothing of it until a more systematic search for cases revealed that those patients were infected with something–what would be known as the Human Immunodeficiency Virus (HIV)–and that the infectious agent was wiping out their immune system. 

Dr. Sharrar: “But we didn't know why they were immunocompromised... [When CDC came up with a case definition...] And in Philadelphia, we had to make the disease reportable. Once the Board of Health made it reportable, then we had the legal authority to collect confidential information on patients, even without their consent. And so we got the Board of Health to pass it, then we established a surveillance system... So we began collecting data on these quote cases and found out that at the very beginning we only had maybe a dozen cases, but they were confirmed cases. They were cases that we had investigated, they met the CDC case definition. And again, they were in a certain population. Now, for the first several years, all we did was watch the epidemic climb. They kept doubling every couple of weeks.” 

But public health would not just watch and do nothing. Dr. Sharrar described how he explained that new disease, AIDS, to the public.

Dr. Sharrar: “We studied the cases that occurred, and we knew from epidemiology very early how that disease was transmitted. And I remember giving a number of lectures to people throughout the city in organizations talking about the epidemic and talking about the modes of transmission. And I said, we know how the disease is transmitted because we look at the disease. And we look at who did not get the disease. And we were able to show using epidemiology that the disease was primarily in gay men, in IV drug users, and hemophiliacs, or in heterosexual persons contacting with individuals that were positive. And we knew that the disease was not transmitted by the food-borne realm. It was not transmitted by the airborne realm. So we gave a lot of assurance to people providing care for them that they weren't going to be infected simply by being around someone that had AIDS. Now that's a very important thing is to be able to explain to the population how the disease is occurring and how you know the disease is occurring.” 

Reflecting on the lessons of those two epidemics, Legionnaires’ Disease and HIV/AIDS, Dr. Sharrar told the students that “It's almost like each generation has to learn on their own. But it was a very important public health issue, and I think we dealt with it as best we could.” 

LaBreshia Taylor: What did you do after leaving the health department? 

Dr. Sharrar described his work with the vaccine program at the health department, and how he vaccinated children. His favorite vaccine is the MMR (measles, mumps, rubella) vaccine, he said. “I was fortunate enough to get a job at Merck, because they had my favorite vaccine. And I was able to monitor the safety profile of that vaccine as it is used in the population.” 

Dr. Sharrar: “It required me to use my understanding of disease surveillance, which I got from public health, my epidemiology, which I got from public health, and my clinical medicine training that I also had. So it was a nice combination. I always felt that I was the public health doc in the pharmaceutical industry. And I liked it. I liked it very much. And I, not only did the MMR, but I did the [other vaccines].” Dr. Sharrar then shared a story of vaccinating about 5,000 children in Iowa, and thought that “[he] probably did more this afternoon in preventing diseases than I would have if I practiced medicine for a full year.” Dr. Sharrar stated how “people don’t appreciate public health until things go wrong. If you’re doing well, and keep things quiet, they don’t even know you exist... Which is fine.” 

Masha Morozov: When did you join The College of Physicians of Philadelphia? 

Dr. Sharrar was invited to join the College in 1976. “I wanted to have contact with the medical community. What I did was public health, and I needed the medical community behind me.” He talked about how he “really did get to meet the leaders of Philadelphia medicine.” He stated the College had many programs to offer, like lectures by Nobel laureates and others. The College, he said, “was a nice combination of social and professional” interactions. When Hilary Clinton was First Lady, she attended an event at The College of Physicians, and Dr. Sharrar remembered fondly the time he met her at that event. 

Dr. Najera: In your view, what is the College’s involvement in public health? 

Dr. Sharrar was part of the initial members of the Section on Public Health and Preventive Medicine. The Section has had many events for students and professionals in public health. Dr. Sharrar had high praise to Susan and Stanley Plotkin for their funding of a Chair of Public Health (currently occupied by Dr. Najera). “Most of the people in public health are pretty busy,” Dr. Sharrar said. “Having this new Chair in Public Health, I think the College now has an opportunity of really becoming involved in public health in Philadelphia.” 

Dr. Sharrar then mentioned how low immunization rates were among the big issues in public health in the 1970s. “We had outbreaks of measles in schools every year,” Dr. Sharrar said. “Another issue is access to care, and the third issue was tobacco.” Dr. Sharrar mentioned how these issues have changed. Today, Philadelphia is facing gun violence, climate change, maternal and child health disparities, and the opioid epidemic. “I know people who are afraid of coming into Philadelphia,” Dr. Sharrar said. He stated he hoped public health could come together to make Philadelphia safer, and to address the other issues of this time. 

Dr. Najera: What advice do you have for future public health professionals, like the three students who joined us today? 

Dr. Sharrar ended the interview by giving some advice to future public health professionals. “Make sure you’re well prepared,” he said. “You need good epidemiology so you understand how and why things are occurring. You need to understand that medicine and public health involves politics, sociology, economics... It’s a combination of things, and you have to learn a lot.” Dr. Sharrar explained that the current media environment distorted issues into being bigger than they were, and vice-versa. “To really know what the real public health issues are that need to be addressed, you need surveillance data,” he said. 

“There’s no end to things that you can get involved in. But I think you're on the right path by beginning with the proper training. Just keep the commitment and don't give up hope.” 

“Good luck in the world. I love seeing this young talent in public health,” he added.