Donald Trump is likely to choose the Johns Hopkins surgeon and writer Martin Makary to lead the Food and Drug Administration, two sources familiar with the matter told Reuters on Wednesday.

Makary raised concerns about a number of public health issues during the Covid pandemic, touting the protection from natural immunity and opposing Covid vaccine mandates.

The FDA is the world’s most influential drug regulator with a more than $7bn budget. It is responsible for approving new treatments and ensuring they are safe and effective before entering the biggest and most lucrative market. It has regulatory authority over human and veterinary drugs, biological medicines, medical devices and vaccines.

The agency is also responsible for maintaining safety standards for the food supply, tobacco, cosmetics, and products that emit radiation.

Brian Hughes, a spokesperson for the Trump transition team, said he would not speculate on or get ahead of any announcement.

As FDA commissioner, Makary would report to the head of the Department of Health and Human Services.

To lead HHS, Trump has nominated Robert F Kennedy Jr, an environmental activist who has spread misinformation about the safety of vaccines and one of several unconventional Trump picks for top administration jobs.

As a doctor, Makary was a co-developer of the Surgery Checklist, a routine for surgeons that improved patient outcomes and has been spread around the globe by the World Health Organization.

His most recent book, Blind Spots, was published in September. In interviews promoting the book, he spoke against what he called “massive overtreatment” in the US that he called “an epidemic of inappropriate care”.

He has advocated for re-examining the use of hormone replacement treatment in menopausal women, reducing overuse of antibiotics and reforms to medical education.

Makary, who lives in Baltimore, has served as an adviser to the conservative healthcare thinktank Paragon Health Institute in Washington.

If confirmed by the Senate, he would succeed Dr Robert Califf, a cardiologist and researcher who also held the role of FDA commissioner in the Obama administration.

In his second term, Califf revamped the agency’s food operations and inspections processes and tried to combat misinformation.