He previously worked as an epidemiologist with the Viral Gastroenteritis Team, Division of Viral Diseases at the U.S. Centers for Disease Control and Prevention (CDC), and prior to that at the Centre for Infections of the Health Protection Agency (now Public Health England) in London. Dr. Lopman's research is directed at understanding the burden of disease, epidemiology and transmission of viral gastroenteritis (mainly norovirus and rotavirus) as well as developing effective methods for their control. He has authored over 175 peer-reviewed publications.