The director of the US National Institute for Allergy and Infectious Diseases and US President Joe Biden's chief medical advisor, Dr Anthony Fauci, has said that booster doses of Moderna's (Nasdaq:MRNA) COVID-19 vaccine may be delayed from rolling out the week of 20 September 2021 as planned, CNN reported on Monday.

Dr Fauci said that while the US administration's plan had been to roll out booster doses of both Pfizer (NYSE:PFE) and Moderna at the same time, that may not happen.

According to Dr Fauci, Pfizer has submitted its information to the US Food and Drug Administration and things looked like they're ready to go. He said Moderna might be a little bit behind that, and if it is, rather than seeing a simultaneous rollout of both products, Moderna could be rolled out a week or two later.

Also, Dr Fauci said the plan is contingent first on the companies submitting the appropriate data to the US FDA, and second, getting FDA approval and then a recommendation from the US Centres for Disease Control and Prevention's (CDC) vaccine advisers.

Dr Fauci added that the good news is that data from Israel shows booster doses offer "profound" protection against infection and hospitalization.

Ultimately, it may turn out the proper COVID-19 vaccination regimen is three doses, Dr Fauci stated.