US President Joe Biden tested positive for COVID-19 on Thursday, underscoring the persistence of the highly contagious virus as new variants challenge the nation’s efforts to restore normalcy after two and a half years of disruption by the pandemic. White House press secretary Karine Jean-Pierre said Biden was experiencing “mild symptoms” and has started taking Paxlovid, an antiviral drug designed to reduce the severity of the illness. He said Biden “will seclude himself in the White House and continue to perform all his duties in full during this time. He has been on the phone with members of the White House staff this morning and will participate in his scheduled meetings at the White House this morning via phone and Zoom from the residence.” Biden, 79, is fully vaccinated, having received two doses of the Pfizer coronavirus vaccine shortly before taking office, a first booster dose in September and an additional dose on March 30. Up until this point, Biden’s ability to avoid the virus seemed to defy the odds, even with the testing procedures in place for those expected to be in close contact with him. Previous waves of the virus have swept through Washington’s political class, infecting Vice President Kamala Harris, cabinet members, White House officials and lawmakers. Biden has increasingly increased his travel schedule and continues to hold large indoor events where not everyone is tested. Top White House officials in recent months have been tight-lipped about the possibility of the president contracting COVID, a measure of how entrenched the virus has become in society — and of the reduced threat to those who are up-to-date on their vaccinations and have access to in treatments. When given within five days of the onset of symptoms, Paxlovid, made by pharmaceutical company Pfizer, has been shown to reduce hospitalizations and deaths by 90% among patients most likely to develop severe disease. In an April 30 speech to more than 2,600 attendees at the White House Correspondents’ Association dinner, Biden acknowledged the risks of attending large events but said it was worth it to attend. “I know there are questions about whether we should gather here tonight because of COVID,” he said. “So we’re here to show the country that we’re getting through this pandemic.” Biden is far from the first world leader – and not the first US president – to contract the coronavirus, which has infected British Prime Minister Boris Johnson, French President Emmanuel Macron and more than a dozen other world leaders and high-ranking officials. When Biden’s predecessor, President Donald Trump, contracted the disease in October 2020, it was a very different time. Vaccines were not available and treatment options were limited and less advanced. After being diagnosed with COVID-19 at the White House, Trump received experimental treatment with antibodies and steroids after his blood oxygen levels dropped dangerously low. He was hospitalized at Walter Reed National Military Medical Center for three days While much of the world has returned to normal after early lockdowns to control spikes in cases and deaths, the virus is still acting as a disruptor to daily life as people are forced to change plans, isolate themselves and calculate their risks of participating in various activities. And after more than two years and more than a million deaths in the U.S., the virus still kills an average of 353 people a day in the U.S., according to the Centers for Disease Control and Prevention. The unvaccinated are at much greater risk, more than twice as likely to test positive and nine times more likely to die from the virus than those who have received at least one primary dose of the vaccines, according to the public health agency. The White House has faced a series of questions about the COVID-19 protocols surrounding the president. Washington’s spring outbreak came weeks after the Centers for Disease Control and Prevention relaxed guidance on face coverings in most of the U.S. As the virus drew closer to Biden, then-White House press secretary Jen Psaki said Biden believed it was “vitally important for him, for his presidency, for the American people” to travel and continue to host large events. He added of Biden: “Like many Americans, he makes risk assessments.” The highly contagious micron variant is the dominant strain in the US, but scientists say it carries a lower risk of serious illness in those who are up-to-date on their vaccinations. The BA.5 substrain, believed to be even more contagious, now accounts for 65% of cases in the US. “There are many infections across America,” White House COVID-19 coordinator Dr. Ashish Jha, blaming the highly contagious strains as well as relaxing mitigation measures such as mask requirements. The coronavirus pandemic helped propel Biden into the White House as he pledged to handle COVID-19 better than his predecessor. After the first few months of success increasing the nation’s vaccine supply and availability, the virus has been a blow to the Democrat’s first year in office as he struggles to boost the nation’s vaccination rate and stay ahead of the unpredictable disease. As cases fell sharply earlier this year, Biden again emphasized his administration’s efforts to end the pandemic and help the nation regain a sense of normalcy. In his March 1 State of the Union address, Biden said it was safe for most Americans to resume their normal pre-pandemic activities, citing declining cases, vaccinations and newly developed treatments. “Tonight, I can say we’re moving forward safely, back to more normal routines,” he said. “It’s time for Americans to get back to work and fill our great centers again.” However, in recent weeks, US officials have urged the public to be cautious once again about the BA.5 variant and have urged the public to seek booster shots if appropriate and for most Americans to consider whether they should wear a face mask in public indoor settings. “We shouldn’t let it disrupt our lives,” Dr. Anthony Fauci, the nation’s top infectious disease expert, said on July 12, “but we can’t deny that it’s a reality we have to deal with.” The White House has sought to go above and beyond public health guidelines to protect the president, with all visitors and staff required to certify their vaccination status or undergo daily testing. Additionally, people expected to be close to Biden are being vetted daily. But Biden has increasingly shown a willingness to participate in larger, indoor events in recent months — activities riskier for contracting the virus — and many have had people not wearing masks. White House officials say Biden was intent on showing he can fulfill his presidential responsibilities without fear of the virus, believing he was well protected from serious consequences “His doctors feel comfortable that he could continue to perform his duties because of all these measures and precautions and protections he has taken,” Psaki said on April 8. In studies, vaccines widely used in the US have been found to protect against serious illness and hospitalization, but new cases have emerged even among those who are fully vaccinated.