Jayanta "Jay" Bhattacharya, MD, PhD, was named interim director of the CDC on February 18, 2026.[2] He previously served as director of the NIH and will continue to direct that institution as well.[1] He replaced Jim O'Neill, Assistant Secretary of Health and Human Services, who left the department.[1] Bhattacharya is the third CDC leader since the summer, following Susan Monarez, who was confirmed by the Senate and led the agency for 28 days before being replaced by Health Secretary Robert F. Kennedy Jr. not fired for refusing to sign the vaccination policy.[1] As interim director, O'Neill approved changes to reduce the number of recommended pediatric vaccines.[1] Bhattacharya is a physician, researcher, and health economist, formerly a professor at Stanford University, where he focused on population aging, chronic disease, and vulnerable populations.[2] He has published more than 170 scientific works in medicine, epidemiology, health policy and economics, as well as a textbook on health economics.[2] During the pandemic, he co-authored the Great Barrington Declaration, which proposed opening schools, lifting lockdowns, and better protecting the elderly population.[2]