Evan Bloch, MD, MS (2010), leverages clinical practice to track and improve population health

Evan Bloch, MD, MS (2010), was recently honored as a 2021 Young Physician-Scientist by the American Society for Clinical Investigation for his contributions to research on whether plasma donated by patients who have recovered from SARS-CoV2 infection can help patients battling the virus. Dr. Bloch’s research efforts have focused on learning about the immunology of COVID-19 from convalescent patient plasma and identifying which immune markers might predict whether convalescent plasma is likely to help recipients.

As Dr. Bloch, like most medical researchers, moved quickly last spring to help address the COVID-19 crisis, he applied the same strategic approach that he had already been applying as a global health researcher and a pathologist specializing in transfusion medicine: studying the blood supply to understand and potentially treat infectious diseases at the population level.

“Blood is a very useful way of accessing populations,” Dr. Bloch said. Because blood banking is a basic part of medical care, the supply offers a readily available biological snapshot of population health.

Local blood supply offers insight into local infectious diseases. In the case of a new disease like COVID-19, infections in donated blood point to the population-wide rate of infection. Individual blood donations also provide a timeline of patients’ immune response to the novel infectious agent.

Dr. Bloch sees the blood supply as “kind of a neglected niche in the global health model. It’s really useful because one can intervene in a whole range of ways.”

“One can use a lot of the tests for blood transfusion to conduct disease surveillance to really get a better understanding of the epidemiology of that agent,” Dr. Bloch said. “Some of the seminal epidemiological studies in West Nile Virus when it hit the U.S. were done using these blood donor cohorts – likewise with COVID-19.”

While new and neglected infectious diseases drove Dr. Bloch’s interest in the IGHS Master of Science program, he now also uses blood supply to identify suboptimal healthcare practices. By way of example, in the early days of the HIV/AIDS epidemic, HIV was found in up to 3% of collected units of blood. There were several high-profile cases of infections that were acquired from blood transfusion. Infected blood recipients, including Ryan White, led to a major rethink of the way blood is solicited, analyzed and treated before it’s given to patients in need. Those modifications have made blood transfusion in high-income countries remarkably safe from an infectious-disease standpoint.

In low- and middle-income countries, collection of sufficient blood to meet demand is a major challenge. Dr. Bloch says educating people on the importance of being a blood donor is important.

“Without availability, one is forced to compromise on safety,” he noted with the somber realism of a seasoned global health practitioner.

Even though his clinical specialty is so conducive to global health research, Dr. Bloch was not introduced to research methods prior to his training in the U.S. As a medical student in South Africa, there was too much clinical material to master. He gained many practical research skills through the M.S. program in Global Health.

“If you look at my projects after the master’s, I’ve essentially used every aspect of that degree, spanning quantitative studies, qualitative studies, mixed methods, policy and health economics,” he said. He also noted that observing the ways researchers with clinical practices blend and balance those interests was very helpful. Dr. Bloch clearly took good notes: He is now an associate professor of pathology and the associate director of transfusion medicine at Johns Hopkins University School of Medicine, with a joint appointment in international health at the Johns Hopkins Bloomberg School of Public Health.