(CNN) Just as more Americans are allowed to visit beaches, attend church indoors or eat inside a restaurant, health officials say gathering in large groups could send states back to where they started.
Texas had its highest single-day increase in new coronavirus cases Saturday, according to numbers from the Department of State Health Services.
The Lone Star State, one of the first to start reopening, reported an increase of 1,801 coronavirus cases on Saturday.
But it's not clear whether the surge is simply due to more testing, or if the virus is spreading more rampantly.
What's clear is that it takes just one infected person to launch a new outbreak.
In Washington state, 87% of a choir developed Covid-19 after one person was infected, the Centers for Disease Control and Prevention said. Two members died.
In California, more than 180 people may have been exposed by a person who had coronavirus during a religious service last week, the Butte County Public Health Department said.
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"At this time, organizations that hold in-person services or gatherings are putting the health and safety of their congregations, the general public and our local ability to open up at great risk," said Butte County Public Health Director Danette York.
"Moving too quickly through the reopening process can cause a major setback and could require us to revert back to more restrictive measures."
Health and Human Services Secretary Alex Azar on Sunday said that there haven't been spikes in cases in the states that have reopened so far, but there are still jumps in places that haven't.
"We are seeing that in areas that are opening, we're not seeing the spike in cases," Azar told CNN's Jake Tapper on "State of the Union." "We still see spikes in some areas that are, in fact, closed, very localized situations."
"So this is going to be really important for us to watch the circumstances on the ground. But, you know, with reopening, what's the key to reopening? First, we need to have good surveillance."
Across the US, more than 1,486,375 people have been infected with coronavirus, and more than 89,549 have died, according to data from Johns Hopkins University.
Where each state stands on the reopening process
Like most states across the country, Ohio is letting go of its stay-at-home restrictions.
"About 90% of our economy is back open because we thought it was a huge risk not to reopen," Gov. Mike DeWine said Sunday.
"But we also know it's a huge risk in opening."
But with greater freedoms come added responsibilities to prevent a resurgence and, in turn, another blow to the economy.
"People have to add that extra layer. We're asking them to put masks on," DeWine said.
And if the situation gets worse, "we're prepared to do what we have to do to pull back," he said.
"We don't want to be like some of the other countries we've seen where they shut down, opened up, and now are starting to shut down again. That is not where we want to be. And it's in everyone's collective hands how we act in the next month or two, whether or not we're going to be in that position."
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In North Carolina, a federal judge granted churches the right to hold indoor services despite an order from the governor prohibiting services with more than 10 people, CNN affiliate WXII reported.
Gov. Roy Cooper's order said larger worship services were allowed as long as they were outdoors.
In a complaint, the plaintiffs said the governor's order "violates the Free Exercise Clause of the First Amendment," according to WXII.
Cooper's office said while it doesn't agree with the decision, it would not appeal. Instead, it urged "houses of worship and their leaders to voluntarily follow public health guidance to keep their members safe."
"We don't want indoor meetings to become hotspots for the virus, and our health experts continue to warn that large groups sitting together inside for long periods of time are much more likely to cause the spread of Covid-19," the governor's office said.
With Memorial Day approaching, beaches on the East and West coasts are starting to welcome visitors again.
In Ocean City, New Jersey, a loudspeaker reminded sun lovers every 15 minutes this weekend to "practice social distancing while walking the boardwalk and beach."
All New Jersey beaches will open next weekend for the Memorial Day holiday and Ocean City took a "dry run" to see how well people respect the social distancing rules.
In California, Los Angeles County was the latest to re-open its shores -- with new rules.
The county requires visitors maintain at least 6 feet from each other and wear face coverings when they're out of the water. Activities such as sunbathing, picnicking, biking and organized sports are still not allowed.
In Tennessee, Graceland -- the home of Elvis Presley -- announced it will reopen Thursday, though tours will operate at 25% capacity.
The US Food and Drug Administration (FDA) has authorized an "at-home sample collection kit that can then be sent to specific laboratories for Covid-19 diagnostic testing."
The kit received an emergency use authorization Saturday. It can be used by people who have already been screened using an online questionnaire that's reviewed by a healthcare provider.
It will allow people to "self-collect a nasal sample at home" using the kit that has been authorized, the FDA said.
"The authorization of a Covid-19 at-home collection kit that can be used with multiple tests at multiple labs not only provides increased patient access to tests, but also protects others from potential exposure," said Dr. Jeffrey Shuren, the director of the FDA's Center for Devices and Radiological Health.
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