The Centers for Disease Control and Prevention's second in command Ralph Abraham resigned Monday because of "unforeseen family obligations," but comes as the agency sees a massive shake-up.

It comes after Health and Human Services Secretary Robert F. Kennedy Jr. ousted CDC Director Jim O'Neill earlier this month, and replaced him with National Institutes of Health Director Dr. Jay Bhattacharya until a new leader is selected. 

The CDC previously stated that Abraham would remain in his role as Bhattacharya took the reins and would work alongside the new acting director.

“Dr. Abraham led with clarity and discipline, advancing the CDC’s mission to protect the health and safety of the American people," the CDC said in a statement on Abraham's exit. "He worked directly with career staff and public health partners to strengthen national preparedness and improve the country’s emergency response efforts. Dr. Abraham chose to step down to address unforeseen family obligations.”

Abraham came into the role after serving as Louisiana's surgeon general, where he faced opposition for pushing the federal government to end its mass promotion of COVID-19 vaccines.

“It has been an honor to serve alongside the dedicated public health professionals at the CDC and to support the agency’s critical mission,” Abraham said in a statement.

Abraham's resignation is effective immediately, the CDC said. No replacement has been named.