Former US presidents Barack Obama, George W Bush and Bill Clinton say they will be publicly immunised for Covid-19 as a sign of their trust that any approved vaccine is safe.
"I may end up taking it on TV or having it filmed, just so that people know that I trust this science and what I don't trust is getting Covid," Mr Obama told SiriusXM radio.
The US Food and Drug Administration has still not approved a vaccine but the agency review of the Pfizer BioNTech vaccine could be completed by December 10, and Moderna's by December 17.
CNN said the former presidents hoped to raise national awareness and create trust in the US health system while encouraging Americans to vaccinate.
"People like Anthony Fauci, who I know and I've worked with, I trust completely," Mr Obama said of the National Institute of Allergy and Infectious Diseases director.
"So if Anthony Fauci tells me this vaccine is safe and can vaccinate – you know, immunise you from getting Covid, absolutely I'm going to take it."
He said he would be publicly vaccinated after first responders and vulnerable people received their shots.
Fifty-eight per cent of Americans surveyed by Gallup say they would receive a Covid-19 vaccine if one were approved today.
Meanwhile, President Donald Trump is concerned about the slow process of the FDA's approval for a Covid-19 vaccine, AP reported.
The possibility of a rushed approval before a vaccine was ready worries Americans, with a poll by Axios/Ispos showing those who are willing to be immunised are most concerned about safety and efficiency.