Dr. Innis trained in internal medicine and infectious diseases at the Walter Reed Army Medical Center. His career has focused on the development of vaccines for infectious diseases, beginning with an assignment to the Dept of Virus Diseases, Walter Reed Army Institute of Research from 1984 to 1999. While there, he supported the development of vaccines against hepatitis A, hepatitis E, dengue, Japanese encephalitis, and adenovirus types 4 and 7. He joined GSK Vaccines in 1999 where he led clinical research programs that supported licensure of 13 vaccines for rotavirus, HPV, MMR, varicella, and seasonal and pandemic influenza. In 2017, he joined PATH to lead the Respiratory Infections and Maternal Immunization Disease Area.