US President Donald Trump on Sunday declared himself immune to Covid-19, saying ready for his second presidential debate with Joe Biden.

Iran Press/America: "It looks like I'm immune for, I don't know, maybe a long time and maybe a short time, it could be a lifetime, nobody really knows, but I'm immune," Trump told Fox News show "Sunday Morning Futures."

"The word immunity means something, having really a protective glow. So now you have a president who doesn't have to hide in a basement like his opponent," Trump added.

US President Donald Trump on Sunday declared himself immune to Covid-19 and ready for a fight as his White House race against surging rival Joe Biden enters its critical final weeks.

But it is not yet clear to what degree contracting Covid-19 confers immunity, with early studies suggesting a few months while newer ones have indicated it could last longer.

During his phone interview on Fox News, Trump, 74, suggested that his White House rival could himself be sick.

"If you look at Joe, he was coughing yesterday horribly and grabbing his mask, as he's coughing," Trump said. "And I don't know what that was all about, and it didn't get much press."

This is while the Biden campaign has been publishing daily coronavirus tests for their 77-year-old candidate since Trump tested positive on October 1.

There has been less transparency surrounding Trump's own state of health, with his medical team repeatedly refusing to say when he last tested negative for the virus. That has fueled suspicions that he may not have been tested for several days prior to his diagnosis.

Covid-19 has killed more than 214,000 people in the United States.

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