Birthday parties and funerals have been blamed for a spike in coronavirus cases as figures showed 21 US states have seen a rise in cases since the country began easing lockdown restrictions.
The number of Covid-19 cases has increased in 21 states in the last fortnight, when many states lifted restrictions to coincide with the three-day weekend for Memorial Day on May 25, according to analysis by the New York Times.
Health officials warned that the US could be facing a second spike of the virus after Americans were pictured in their thousands sunning themselves on crowded beaches and swimming pools over the long weekend.
The warnings have proved prescient in light of the latest figures. More than a dozen states and the US territory of Puerto Rico have recorded their highest seven-day average of new cases since the pandemic began, according to data from the Washington Post. In at least nine states hospitalisation rates have also seen a steady increase since Memorial Day.
Texas, one of the first states to ease restrictions in place because of Covid-19, had seen a decline in the number of new daily cases until May 25, when the numbers began to sharply rise once more.
Figures from the most recent day, June 9, show the state reported 1,945 new covid-19 cases, up from 445 new cases on May 25, according to data collected by the New York Times.
On Wednesday the state also reported record numbers of coronavirus-related hospitalisation rates for the third consecutive day, with 2,153 patients in hospital.
On Saturday Florida reported 1,426 new cases, its highest number since early April. The state's governor, Ron DeSantis, has played down suggestions that the spike is linked to his early efforts to reopen businesses, instead pointing to higher testing rates.
Justin Bahl, an epidemiology and biostatistics professor at the University of Georgia, said that the national percentage of positive cases was approximately 11 per cent, but most states were recording between six and ten per cent positive cases.
"This suggests that we’re doing enough testing and that the increases we’re seeing is real and not an artifact of increased testing," he told The Telegraph.
Prof Bahl added that there were likely to be multiple causes to the increase. "Certainly, large gatherings and increased community contacts play a large role. Memorial Day likely contributed to the spread, but community contacts and relaxed social distancing will sustain the spread," he said.
Officials in California, which began reopening in early May and has reported record numbers of new cases in recent days, said family gatherings such as birthday parties and funerals were driving the increase.
Contact tracing teams in the state's capital, Sacramento, said they had seen a notable rise in new cases and hospitalisation rates in the last fortnight as they warned against group gatherings inside homes.
Dr Olivia Kasirye, the health officer for Sacramento County, said that despite state orders banning such gatherings, the reopening of restaurants, shops and hair salons had given people a false sense of safety.
However the California governor, Gavin Newsom, has said he will push ahead with the next phase of reopening, which includes bars and cinemas, and is scheduled for Friday.
“We’ve made it abundantly clear that we anticipate an increase in the total number of positive cases,” Mr Newsom told reporters, but he added that the state was far better prepared to handle an outbreak now, with increased testing capacity and millions of masks available.
Among the worst new outbreaks across the US is Maricopa county in Arizona, which includes its capital Phoenix, and has reported more than 4,000 cases so far this month. A rise in cases has also been reported in several other counties in Arizona, which experts have linked to the end of stay-home orders on May 15.
Meanwhile Alaska, where the number of new infections hovered around just one patient per day in early May, has reported its worst figures since the pandemic began. There have been more than 100 new cases in the past week alone, bringing the state’s total number of cases to 620.
The White House played down the increase in cases on Wednesday, with press secretary Kayleigh McEnany saying: "You've got to look in a nuanced way at each of these states. For instance Texas is one of the places where they're seeing we're seeing a steady slope not a huge rise but part of it's due to the fact that they're testing in long term care facilities and in prisons and the more testing you do the more you identify."
It comes as demonstrators across the nation have taken to the streets in their thousands to protest against police brutality, sparking fears the number of new cases could rise higher still. Several new infections have already been linked to the protests, with National Guard troops in Nebraska and Washington DC testing positive for the virus after policing protest events.
Dr Anthony Fauci, America's top infectious disease expert, said he was "very concerned" by the sight of crowds of protesters ignoring social distancing rules and not wearing masks.
"It's a perfect setup for further spread of the virus in the sense of creating these blips which might turn into some surges," Dr Fauci told WTOP radio.
However Mike Pence, the US vice president, reportedly told state governors that the country would forge ahead with reopening despite concerns that the protests may have prompted a second spike.