Dr. Alyssa R. Letourneau received an Sc.B. in neuroscience from Brown University and an M.D. from Yale University School of Medicine. She subsequently completed her residency in internal medicine and pediatrics at Massachusetts General Hospital and a fellowship in infectious diseases at Massachusetts General Hospital and Brigham & Women's Hospital. During her training, she received the Edward Kass Award for Clinical Excellence from the Massachusetts Infectious Disease Society and completed her Master of Public Health at the Harvard School of Public Health. She completed an additional year of clinical training in caring for immunocompromised hosts at Brigham & Women's Hospital and the Dana-Farber Cancer Institute.

Dr. Letourneau is the Director of the Massachusetts General Hospital Antimicrobial Stewardship Program and an Assistant Professor of Medicine at Harvard Medical School. She cares for patients both inpatient and in the clinic. Her clinical interest is seeing immunocompromised hosts including patients with leukemia, lymphoma, those who have undergone stem cell transplant or CAR-T as well as patients who will undergo immune modulating therapy. She also has expertise in managing patients with multi-drug resistant organisms. 

In 2021 and 2022 she was awarded the MGH-BWH Infectious Disease Fellows Faculty Teaching Award given to a faculty member for outstanding clinical education of the fellows. In 2023, she became a Fellow of the Infectious Diseases Society of America and was honored as a Top Doctor in Boston by Boston Magazine.