Donald Trump has claimed he no longer has coronavirus and is now “immune” to Covid-19 as he prepares to return to the campaign trail on Monday for a barrage of rallies in swing states in his pursuit of a second term in the White House. Numerous opinion polls have continued to show the US president trailing his Democratic challenger Joe Biden by a significant margin nationally, adding urgency to Trump’s desire to get back to the in-person appearances he believes are key to his success on the 3 November election day. He will appear at a rally in Sanford, Florida, on Monday night and follow up with events in Pennsylvania and Iowa on Tuesday and Wednesday, all closely-contested states he won by thin margins in 2016 but now appear to be leaning towards Biden. Yet questions remain over the state of the 74-year-old president’s health following his infection with Covid-19 and a three-night stay in the Walter Reed military medical center in Maryland. He was discharged one week ago, but the White House and medical professionals have refused to release details on his lung scans or when he last tested negative for Covid-19. In a wide ranging 30-minute interview on Fox News on Sunday, Trump insisted he was completely free of the virus, without providing medical evidence, and further claimed, implausibly, he was immune after receiving an experimental cocktail of antibodies, antiviral drugs and steroids during his hospital stay. “To me it’s a cure, it’s much more than a therapeutic,” Trump said. “Once you’ve recovered, you’re immune. I am immune… maybe for a short time, maybe for a long time. The president is in very good shape,” Trump said, adding that immunity gave him a “protective glow”. There are, however, some documented cases of patients who have recovered from coronavirus being reinfected. Later on Sunday, Twitter flagged a tweet in which Trump claimed he was immune to the coronavirus, saying it violated the social media platform’s rules about misleading information related to the pandemic. “A total and complete sign off from White House Doctors yesterday. That means I can’t get it (immune), and can’t give it. Very nice to know,” Trump said in the tweet. “This Tweet violated the Twitter Rules about spreading misleading and potentially harmful information related to Covid-19,” Twitter’s disclaimer read. A Twitter spokeswoman told Reuters that the tweet made “misleading health claims” about Covid-19 and that engagements with the post would be “significantly limited”, as is standard in such cases. The White House physician who oversaw Trump’s treatment at Walter Reed has spoken only in general terms about the president’s condition. In a memo released late on Saturday, Dr Sean Conley cleared Trump to return to public events, saying “he is no longer considered a transmission risk”. Like previous bulletins, it did not reveal if Trump had tested negative for Covid-19, only that the medical team could not find evidence of the virus replicating in his body. There is no approved test to determine how long a person remains contagious after contracting coronavirus. On Saturday, Trump appeared in public for the first time since his hospitalisation, delivering an 18-minute address to hundreds of supporters from a White House balcony, loosely themed around “law and order”, touching on other election issues including the economy and touting his handling of a pandemic that has killed more than 214,000 Americans and infected more than 7.7 million – far more than any other country. He exhibited few outward signs of his encounter with the virus, other than sounding a little hoarse. He also did not wear a mask during his speech, along with many in the crowd, who were packed tightly together in front of the South Lawn balcony in contravention of government guidance on social distancing. A spokesperson for Biden’s campaign called the Saturday event “stunningly reckless and irresponsible”, pointing to another gathering at the White House two weeks earlier when few wore masks or distanced, and at which more than 20 key Trump aides and Republican politicians, including two top senators, are thought to have contracted the virus. Trump campaign officials have been keen to get the president back in front of supporters, believing his enforced absence from the hustings at least partially accounts for slumping opinion poll numbers that see him trailing Biden by up to 16 points in some surveys nationally. Democrats, meanwhile, remain cautious about their candidate’s advantage, aware that Hillary Clinton won the popular vote by more than three million ballots in 2016 but lost the White House in the state by state contests for electoral college votes that determine the winner. In many state races this year, including almost all of the key battleground states such as Florida, Pennsylvania, Iowa, New Hampshire and Ohio that Trump needs to hold on to, Biden is polling ahead, although by much smaller margins than nationally. On Monday, Biden will be pitching to working families at his own event in Toledo, Ohio, where Trump trails his challenger by little more than a half percent in the latest FiveThirtyEight analysis. “Democrats generally are very positive to Joe Biden, but they are extraordinarily negative to Donald Trump. So in many ways, Trump is the Democrats’ greatest get-out-the-vote argument,” said Charles Franklin, director of the Marquette Law School poll in Wisconsin, where Biden leads 46-41%. Also on Monday, confirmation hearings begin in the US Senate for Amy Coney Barrett, Trump’s conservative pick for the supreme court to replace long-serving liberal Justice Ruth Bader Ginsburg, who died last month at 87. Barrett’s controversial nomination has drawn criticism from Democrats, who fear her right-leaning ideology will secure a conservative skew to the nation’s highest court for a generation, and threaten established legal precedent such as affordable healthcare and abortion rights. They are also angry that the Republican Senate majority is attempting to force through Trump’s choice just weeks before the election. In 2016, Republicans successfully blocked Barack Obama’s supreme court pick Merrick Garland, arguing that it was wrong to seat a supreme court justice in an election year. Some Republican senators have likened the upcoming battle over Barrett’s confirmation to “a holy war”, believing that Democratic attacks on her Catholic beliefs could win them votes next month. Dick Durbin, the Democratic Senate minority whip and member of the Senate judiciary committee that will explore Barrett’s candidacy, said the American people saw it in far simpler terms. “This makes a difference in their life,” he said in an interview on NBC’s Meet the Press. “Once Republican voters wake up to the reality and strategy, many are going to say to their senators, ‘Listen, this is not what we bargained for, we may be conservatives but we’re not crazy. My family needs health insurance protections’.” Chris McGreal and Reuters contributed to this report