(CNN) -- As Americans head into a holiday weekend in the shadow of a ravaging coronavirus pandemic, some governors are rethinking their stance on face coverings after days of record infections.
The US reported more than 52,000 new cases of the virus on Thursday, a new daily record surpassing one set the previous day.
More than two months after the first peak affected just a handful of states the virus is surging again across the South and Southwest. The Centers for Disease Control and Prevention projects nearly 148,000 deaths in the US by the end of the month.
"What we're seeing now in the Southwest is a surge in both the number of positive cases and the percent of people testing who are positive," Dr. Jonathan Reiner, a CNN medical analyst and professor of medicine at George Washington University, said on Friday.
"There's no question about it. The virus is surging in large parts of the United States."
Coronavirus has killed more than 128,000 people and infected over 2.7 million nationwide, according to Johns Hopkins University. Infection rates are rising in 36 states, with patients rapidly filling hospitals across the South and West.
California, Arizona, Texas and Florida all posted record new cases this week -- Florida reported more than 10,000 additional coronavirus cases on Thursday while Texas had about 8,000.
On Friday, the Sunshine State reported 9,488 additional cases, bringing its total to 178,594. Florida is now averaging more new cases per day -- 7,870 -- than any other state, according to a CNN analysis of data from Johns Hopkins University. California and Texas trail close behind.
Nearly two dozen states have paused their reopenings to combat the spread while others have taken extra measures to keep it out of their borders. New York, New Jersey and Connecticut issued a travel advisory that requires people arriving from eight states with high coronavirus rates to quarantine for two weeks.
Here are other significant developments this week:
Masks alone cannot help combat coronavirus
Some state leaders have blamed the spike in new cases on more testing. But experts attributed it to increasing infections caused by a lack of a comprehensive response.
"If you turn your back on the virus, if you turn your back on science, it's going to bite you," said Dr. Thomas Frieden, the former director for the Centers for Disease Control and Prevention.
"And that's what's happening in most of the US, where we're seeing increases, and in some places, really fast increases of the virus."
Contrary to what people think, he told CNN's Chris Cuomo, the virus cannot be stopped by a single measure.
"Whether it's restricting travel or staying home or testing a lot of people or wearing a mask. And those are all important, but none of them, in and of themselves are going to control this," he said. "You basically need to physically distance. The three Ws: wear a mask, wash your hands, watch your distance, and you need to box the virus in with strategic testing, effective isolation, rapid contact tracing and supportive quarantine. We're not doing that yet in most of the country."
Officials fear July Fourth could bring a surge in cases, and are urging Americans to limit their festivities to avoid outbreaks. The holiday weekend could be the "perfect storm" for a spike in coronavirus cases due to travel, easing restrictions and people not following preventive guidelines, said Dr. Joshua Barocas, an infectious disease physician at Boston Medical Center.
Virus has mutated to become more infectious
The guidance is especially relevant following new research that the virus has mutated to become more infectious.
A global study found strong evidence that a new form of coronavirus has spread from Europe to the US. The new mutation makes the virus more likely to infect people but does not seem to make patients any sicker than previous variations of the virus, an international team of researchers reported Thursday.
"It is now the dominant form infecting people," said Erica Ollmann Saphire of the La Jolla Institute for Immunology and the Coronavirus Immunotherapy Consortium, who worked on the study. "This is now the virus."
The team checked more genetic sequences and ran experiments involving people, animals and cells in lab dishes that show the mutated version is more common and more infectious than other versions.
The new version seems to multiply faster in the upper respiratory tract -- the nose, sinuses and throat -- which would explain why it passes around more easily, the researchers said. But tests on 1,000 hospitalized coronavirus patients showed those infected with the new version did not fare any worse than those who caught the original strain.
"We do know that the new virus is fitter. It doesn't look at first glance as if it is worse," Saphire said.
The study was published in the journal Cell and confirms earlier work suggesting the mutation made the new variant of virus more common.
Thousands more deaths projected this month
The Centers for Disease Control and Prevention now projects nearly 148,000 coronavirus deaths in the United States by July 25.
US Surgeon General Dr. Jerome Adams on Friday urged caution about the death rate for the virus remaining flat while the number of new cases increases.
"We know deaths lag at least two weeks and can lag even more," Adams said on "Fox & Friends."
"In the beginning, nursing homes were hit really hard, and the majority of our deaths were occurring on people who were 60, 65 and older. Now the majority of cases are in people who have an average age of 35, and so those folks are going to have less comorbidities, they're going to be less likely to end up in the hospital and to die."
He added, "What we're really worried about -- particularly with young people -- is that they get it and then they spread it to their grandmother, to their grandfather."
This week's national forecast relies on 24 individual forecasts from outside institutions and researchers. The new projections published Thursday offer the projection with a possible range of about 139,000 to 161,000 deaths.
"The state-level ensemble forecasts suggest that the number of new deaths over the next four weeks in Arizona, Arkansas, Florida, Idaho, Nevada, Oklahoma, Oregon, South Carolina, Texas, Utah and Wyoming will likely exceed the number reported over the last four weeks," the CDC said on its forecasting website.
"For other states, the number of new deaths is expected to be similar to the number seen in the previous four weeks or to decrease slightly."
Unlike individual models, the CDC's ensemble forecast offers projections for the next month.
More states make sweeping mask mandates
When mask mandates for Texas and Kansas go into effect Friday, 19 states and Washington, DC will have such requirements.
In a major change of heart, Texas won't allow people who are in counties with 20 or more active Covid-19 cases to go out without a face covering. About 95% of Texans live in those areas.
"We have the ability to keep businesses open and move our economy forward so that Texans can continue to earn a paycheck, but it requires each of us to do our part to protect one another -- and that means wearing a face covering in public spaces," Texas Gov. Greg Abbott said.
Texans younger than 10 and people who have a medical condition that prevents them from wearing a mask are exempted. Repeat violations can result in a fine, the order says.
Other governors have also issued statewide orders, including California, Connecticut, Delaware, Hawaii, Illinois and Michigan.
It's not possible to pinpoint what caused the current spike in coronavirus cases, said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. But it's likely a result of a series of events that occurred simultaneously, including protests, Memorial Day festivities and states reopening, he told the Harvard Business Review.
Of the 36 states whose new cases have gone up this week compared to the previous one, nine of them have increased by over 50%. They are Montana, Idaho, Nevada, Florida, Georgia, Tennessee, Louisiana, Alaska and Delaware.
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