More than half of U.S. states over the past two weeks have seen increases in their daily numbers of newly reported coronavirus cases—and officials have reported that new outbreaks of the virus are occurring among Americans visiting certain places and taking part in certain activities.

What makes a Covid-19 patient a 'superspreader'?

Newly reported coronavirus cases are resurging in more than half of US states

The United States' coronavirus epidemic had seen a downward trend in newly reported cases for six consecutive weeks, as states had closed nonessential businesses, implemented stay-at-home orders, and imposed social distancing and other protocols to curb the virus' spread.

However, the country's daily number of newly reported coronavirus cases now has grown for more than a week and has surpassed the record-high levels the country reported in April, during the previous peak of the epidemic. U.S. officials on Wednesday reported 36,880 new cases of the coronavirus, which is the largest single-day increase in new cases that the country has reported so far.

Some public health experts have said the recent acceleration in newly reported cases could stem from states reopening nonessential businesses and ending stay-at-home orders, as well as Americans relaxing social distancing practices. According to data compiled by Johns Hopkins University, U.S. officials on Saturday reported the country's largest single-day jump in newly reported cases since May 1, when many states first began easing stay-at-home orders and other measures aimed at curbing new the coronavirus' spread.

Where are Americans getting infected?

Throughout the country, officials are reporting that clusters of new coronavirus cases are cropping up among Americans who are easing social distancing practices; visiting bars, restaurants, and other businesses; and visiting churches and attending large social gatherings.

Houses of worship

According to the New York Times, houses of worship have been tied to many coronavirus outbreaks throughout the country, including outbreaks in Alabama, Kansas, Oregon, and West Virginia.

In Union County, Oregon, for example, officials had reported just eight cases of the new coronavirus by early June. However, the county's number of cases swelled to more than 250 by June 20. According to the Times, most of those new cases were tied to an outbreak of coronavirus transmission at a local church. Paul Anderes, a Union County commissioner, said he was "a little bit surprise[ed]" when the county's cases started to rise, "because so many people for so long were following stay-at-home" guidance.

In West Virginia, Gov. Jim Justice (R) said six coronavirus outbreaks in the state have been linked to gatherings at churches, including three outbreaks that still were active as of last week. Justice said while he doesn't plan to order churches in the state to close. the outbreaks demonstrate that, when church congregants fail to properly social distance and wear face masks or coverings, "[t]he reality is really simple … we're asking for it."

Bars, public venues and events

Other establishments, such as bars and other public venues, also have been linked to new clusters of coronavirus cases.

California is one of the 26 states that has seen a spike in its daily number of new coronavirus cases over past couple weeks. According to the Los Angeles Times, San Diego County, alone, reported eight new coronavirus outbreaks in the seven days leading up to June 22. One of those outbreaks involves people who visited a campground, and another involves people who visited a "social club," county officials said.

In Baton Rouge, Louisiana, more than 100 people tested positive for the coronavirus after visiting bars in an area of the city. And in Florida, which this week became the seventh state to report more than 100,000 cases of the new coronavirus, officials have linked 152 recent cases to one bar in Orlando, according to Raul Pino, a state health officer in the city.

"A lot of transmission happened there," Pino said. "People are very close. People are not wearing masks. People are drinking, shouting, dancing, sweating, kissing and hugging, all the things that happen in bars. And all those things that happen are not good for Covid-19," the disease caused by the new coronavirus.

Las Vegas also has seen a spike in new coronavirus cases after allowing casinos to reopen on June 4, with the city's daily average of new cases doubling from 124 to 250 within two weeks, the New York Times reports. According to the New York Times, several employees of casinos, hotels, and restaurants in the city have tested positive for the virus.

Some recent outbreaks also have been tied to athletic events, as both student and professional athletes have begun returning to their sports, the New York Times reports.

According to the New York Times, at least 23 football players at Clemson University have contracted the virus, as well as 10 athletes at Iowa State University and five at Texas State University. Some professional sports teams also have reported new coronavirus cases among athletes.

Parties and social gatherings at people's homes

New clusters of coronavirus cases aren't just occurring among Americans visiting public venues. They're also being seen among Americans gathering at people's homes, officials say.

In Washington, for example, contact tracers have linked at least 29 cases of the new coronavirus to a party held in early June, which also lead to potential exposure at 31 employers. "We're finding that the social events and gatherings, these parties where people aren't wearing masks, are our primary source of infection," Erika Lautenbach, director of Washington's Whatcom County Health Department, said. "And then the secondary source of infection is workplace settings. There were 31 related employers just associated with that one party because of the number of people that brought that to their workplace. So for us, for a community our size, that's a pretty massive spread."

"We have found as businesses begin to open up, for some people, there was a sense that things are OK now, and they began having gatherings in the home and birthday parties," Sacramento County Health Officer Olivia Kasirye said. She noted that such events typically involve people being "together for an extended period of time," often not wearing face masks or coverings and not keeping six feet of physical distance between them. "That is most of the exposure," she said.

And Kasirye noted that the in-home events can put vulnerable Americans at risk. "They are multi-generational" and have attendees "with higher risk" of developing severe cases of Covid-19, she said.

Experts worry resurgence could overwhelm hospitals

Rebecca Christofferson, an infectious-disease expert at Louisiana State University, said the new coronavirus outbreaks are "exactly what most people would expect when you lift stay-at-home orders and isolation orders." She explained that—between states reopening nonessential businesses and Americans getting fatigued with following social distancing guidelines, the country could have a hard time curbing the virus' spread once again.

"All of those things combined just make it a complex problem—human behavior, contact, and virus. … You put it all in a big pot, and boom!"

Some public health experts are concerned that more Americans will start taking part in social gatherings as states continue moving forward with their reopening plans, which could lead to more so-called "superspreader" events—and the resulting surge in new coronavirus cases could overwhelm hospitals.

Officials in Washington's Yakima County, for instance, already are seeing a new surge in coronavirus cases that is overwhelming local hospitals, with providers having to send some patients outside of the county to receive care.

“We are frankly at the breaking point," said Washington Gov. Jay Inslee (D), this past weekend. "We don't want to see people in parking lots unable to get hospital care. And if we do not act aggressively now [to curb new cases], that is what's going to happen."

Marc Boom, CEO and president of Houston Methodist Hospital, said the number of coronavirus patients at the hospital has tripled since Memorial Day—and he warned that hospitals could be overwhelmed with new cases within weeks.

"It is snowballing," Boom said. "We will most certainly see more people die as a result of this spike."

Boom urged people who choose to go to bars and restaurants to wear face masks or coverings and be conscious of social distancing.

"It is possible to open up at a judicious pace and coexist with the virus," he said, "but it requires millions and millions of people to do the right thing," (Mervosh et al., New York Times, 6/22; Lin, Los Angeles Times, 6/22; Lush et al., Associated Press, 6/23; Alvarado, Daily Beast, 6/23; Silva, NPR, 6/24; New York Times, 6/25).