Dr. Lawrence A. Tabak, the principal deputy director of the National Institutes of Health (NIH), has unexpectedly stepped down from his position. Having served at the NIH for 25 years, Tabak held the second-highest rank within the agency and acted as its director during the COVID-19 pandemic. His tenure included scrutiny from Republicans regarding the NIH's pandemic response, often alongside Dr. Anthony Fauci.

In an email reportedly sent to NIH staff earlier this week, Tabak, 73, announced his retirement from government service, effective immediately, without providing a specific reason for his departure. His resignation coincides with a period of transition at the Department of Health and Human Services (HHS), the NIH's parent organization, following the start of President Trump's new term. The administration has implemented program cuts and reportedly plans personnel changes within HHS. While Tabak might typically have been expected to serve as acting director during such transitions, the role was instead filled by Dr. Matthew Memoli, a former NIAID researcher and critic of COVID vaccine mandates.

Congressional investigators have previously implicated Tabak, along with Fauci and former NIH Director Francis Collins, in alleged attempts to influence the narrative surrounding COVID-19's origins. GOP investigations revealed Tabak's participation in a controversial phone call with these figures and other scientists. Critics contend this call led to the publication of a scientific paper downplaying the lab leak theory.

Tabak also faced scrutiny regarding investigations into potential gain-of-function research at the Wuhan Institute of Virology. He was criticized for perceived delays in providing information requested by Republican investigators on this matter. Following his resignation, former NIH colleague Jeremy Berg described Tabak as someone who handled difficult situations and often bore the brunt of responsibility when issues arose.

Fox News Digital contacted the NIH for comment but did not receive a response.