NIEHS Director Rick Woychik, Ph.D., has announced his selection of Michael Fessler, M.D., as the permanent Clinical Director of NIEHS effective Dec. 29, 2024.
“Dr. Fessler’s unique combination of clinical and scientific expertise, intellect, thoughtfulness, and leadership make him ideally suited to advance the intramural Clinical Research Program at NIEHS,” said Woychik. “I am confident he will be an outstanding Clinical Director who will help lead NIEHS in bold and exciting new directions that will keep us at the cutting edge of environmental health sciences research.”
Fessler had served in an acting role since July, when longtime NIEHS Clinical Director Janet Hall, M.D., announced she would be stepping away from her role (see sidebar).

Translating scientific findings
Fessler is a physician by training with expertise in basic and translational approaches for studying innate immunity. In his new role, Fessler’s responsibilities will include identifying opportunities to translate basic science discoveries made at NIEHS into clinical studies, and to create an environment in which clinical findings influence the direction of laboratory studies.
“Bridging the divide between laboratory research and clinical practice to improve human health is something I am passionate about as I take on this role,” said Fessler.
To that end, Fessler will be responsible for developing long-range clinical research goals and objectives relevant to the mission of NIEHS, in addition to facilitating research collaborations between scientists inside and outside of NIEHS. He will also ensure NIEHS research meets high standards of scientific excellence and ethical conduct, overseeing the review of matters related to patient care in research protocols and the recruitment of clinical staff.
Fessler’s journey to clinical director
Prior to joining NIEHS, Fessler received his B.A. in philosophy from Princeton University and his M.D. from Harvard Medical School. He completed his internal medicine residency at Massachusetts General Hospital, along with a pulmonary-critical care medicine fellowship at the University of Colorado Health Sciences Center.
Fessler joined NIEHS in 2006 as an investigator in the Intramural Research Program. He has served as the chief of the Immunity, Inflammation, and Disease Laboratory since 2018. Fessler also leads the Clinical Investigation in Host Defense Group, a group that defines mechanisms of the immune response and translates them to human disease. In 2020, he was awarded the National Institutes of Health Director’s Challenge Innovation Award for his research looking at the links between inflammation and lung infection.
“Moving forward, we’re in a very exciting new epoch of clinical research at NIEHS due to the outstanding foundational work done by Jan Hall and others,” Fessler said. “I’m very excited about the emerging era of precision environmental health, in particular, understanding how different exposures at the individual level change disease susceptibility in a way that might be clinically actionable.”
(Sam Tyler is a technical writer-editor in the NIEHS Office of Communications and Public Liaison.)