Several US senators attended event with Covid-infected Lindsey Graham

Senior Republican senator says he has contracted coronavirus even after being fully vaccinated

US Senator Lindsey Graham speaks on Capitol Hill. Reuters

Several members of the US Congress have said they attended the same outdoor event as Lindsey Graham, the senior Republican senator who said he has tested positive for Covid-19 even after being fully vaccinated.

Mr Graham on Monday became the first senator to disclose a breakthrough infection, saying he was “very glad” he had received the vaccine, without which his current symptoms would be “far worse".

The news prompted several other members of Congress to take Covid-19 tests and report their status. A handful of senators spent part of the weekend working and socialising with Mr Graham, who attended a gathering on Joe Manchin's houseboat the evening he first developed symptoms.

NBC News reported that other senators aboard the houseboat included Mark Kelly, Chris Coons, Jacky Rosen, Catherine Cortez Masto, Maria Cantwell and John Thune, though representatives for several of the senators present at the event say none have tested positive.

Mr Manchin said the outdoor event, which lasted several hours, was “just trying to get people together".

In a statement issued on Monday afternoon, Mr Graham said he “started having flu-like symptoms Saturday night” and went to the doctor on Monday morning.

After announcing his positive test, Mr Graham said he would quarantine for 10 days.

More senators have donned masks in recent weeks as coronavirus case counts have risen, but they are not required in the Senate chamber, and some still choose not to wear them. The House of Representatives has returned to a mask requirement.

Roy Blunt, a Republican senator who has been vaccinated, was not wearing a mask on Monday and said he had not decided whether to put one back on. He said he is concerned that reports of Mr Graham’s illness will discourage some from being vaccinated.

Vaccinations and mask use in the US remain deeply polarising issues, with millions of people hesitant to be inoculated, often due to misinformation about the safety or efficacy of the shots.

On wearing a mask, Mr Blunt said, “I think it actually is one of the reasons that people are encouraged to get the vaccine is they don’t have to. There’s no way to know just how risky it was for the people who were near Graham — vaccinated or not. Vaccinated people are at a much lower risk of being infected at all and for contracting a serious case.”

The Centres for Disease Control and Prevention (CDC) has reported that fully vaccinated people determined to have been in close contact with someone who has Covid-19 do not need to quarantine if they are asymptomatic but should be tested within five days and wear a mask indoors for 14 days, or until they test negative.

The Centres for Disease Control and Prevention (CDC) has reported that fully vaccinated people determined to have been in close contact with someone who has Covid-19 do not need to quarantine if they are asymptomatic but should be tested within five days and wear a mask indoors for 14 days, or until they test negative for the disease.

Mr Graham, who was vaccinated in December, has long been a proponent of vaccination, saying during a visit this spring to the Medical University of South Carolina in Charleston that “the sooner we get everybody vaccinated, the quicker we can get back to normal".

His infection comes on the heels of updated CDC guidance urging even fully vaccinated people to return to wearing masks indoors in areas of high coronavirus transmission, citing the surge of the highly contagious Delta variant.