Maria Deloria Knoll is a senior scientist at Johns Hopkins Bloomberg School of Public Health. She also serves as the associate director of science for the International Vaccine Access Center. Knoll is an epidemiologist with a focus in the technical analytical challenges of policy-driven research pertaining to the design, conduct and analysis of epidemiological studies and clinical trials that evaluate vaccines and vaccine-preventable diseases. She directs the analysis of a 7-country pneumonia case-control study to determine the causes of pneumonia in developing country settings to guide the development of new pneumonia vaccines and treatment algorithms.