Bourla, 60, said he had started a course of the company's oral COVID-19 antiviral treatment, Paxlovid, and was isolating and following all public health precautions.

"I am confident that I will have a speedy recovery," Bourla said in a statement.

Several public figures have tested positive for the infectious disease in the past few months including U.S. President Joe Biden and his chief medical adviser, Dr Anthony Fauci.

Biden spent more than two weeks isolated in the White House after two bouts with COVID-19, the second instance is believed to be a "rebound" experienced by some COVID patients who take Paxlovid.

Paxlovid is an antiviral medication that is used to treat high-risk people, such as older patients.

Bourla has received four doses of the COVID vaccine developed by Pfizer and its German partner BioNTech.