Former president Donald Trump on Tuesday encouraged his Republican supporters -- one of the main groups resistant to Covid-19 vaccines -- to get their shots.

"I would recommend it," Trump said during an interview on Fox News.

"I would recommend it to a lot of people that don't want to get it and a lot of those people voted for me, frankly," he said.

"It's a great vaccine, it's a safe vaccine and it's something that works."

This was Trump's most explicit endorsement for the national mass vaccination campaign since he left office in January.

All other living former presidents, including Democrat Barack Obama and Republican George W. Bush, have delivered high profile public service announcements.

Donald Trump
Until speaking on Fox News, former US president Donald Trump had been largely silent on the subject of the national vaccine rollout against Covid-19 Photo: AFP / MANDEL NGAN

But Trump has largely been silent while the man who defeated him, President Joe Biden, masterminds the vaccine rollout.

Polls show that Republican men, who are overwhelmingly supporters of Trump and his "Make America Great Again" or MAGA platform, are the leading vaccine skeptics.

Meanwhile, Trump remained non-committal about seeking to recapture the presidency following his one term in office.

"Based on every poll, they want me to run again," he said. "But we're going to take a look and we'll see."

Trump spoke a day after the White House suggested he shouldn't be waiting for an "engraved invitation" to join the public campaign encouraging Americans to take Covid-19 vaccines.

"Every other living president... has participated in public campaigns. They did not need an engraved invitation to do so. So he may decide he should do that. If so, great," Biden's press secretary, Jen Psaki said.

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