Dr. Lewnard studies the natural history, transmission dynamics, and control of infectious disease agents, with a focus on respiratory and vaccine-preventable pathogens. Much of his work has addressed the response of the bacterial pathogen Streptococcus pneumoniae to multivalent conjugate vaccines. His work encompasses field-based studies as well as mathematical modeling and development of causal inference methods, in particular for studies of vaccine impact and effectiveness.
The value of vaccines in reducing the burden of antimicrobial resistance has been a particular focus of Dr. Lewnard’s recent work, capped by a seminal 2020 study demonstrating substantial reductions in antibiotic consumption among children in low- and middle-income countries due to pneumococcal and rotavirus vaccines. Ongoing projects address related impacts of vaccines in development against group A Streptococcus, RSV, and Shigella.
During the ongoing pandemic, Dr. Lewnard has redirected substantial research effort to COVID-19 in the US as well as in India, with outputs including the first in-depth study of SARS-CoV-2 epidemiology and transmission dynamics in a low-resource setting. He has worked closely with Kaiser Permanente to aid operational planning and in studies of COVID-19 epidemiology. Parallel to these efforts, he has co-led a study of SARS-CoV-2 infection among California farmworkers, demonstrating over 4-fold higher prevalence of infection compared to the general population amid substantial health disparities.
Dr. Lewnard joined the faculty of the School of Public Health at UC Berkeley in 2018 after postdoctoral work with Marc Lipsitch at Harvard TH Chan School of Public Health. He earned a PhD in Epidemiology of Microbial Diseases from Yale University in 2017.