The pandemic is still in its early stages, one expert says

And the pandemic is still in its early stages, said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.

A total of 56,750 cases of Covid-19 and 372 virus-related deaths were recorded in the US on Monday, according to Johns Hopkins University's tally of cases. At least 3,830,010 coronavirus cases have been identified. More than 140,900 people have died.

To help combat the spread of the virus, at least three mayors have mentioned reverting back to tighter measures, and nearly 40 states have some type of mask requirement in place. Masks, experts have said, are one of the most powerful tools to prevent further infections.

But keeping people apart is just as important, Osterholm stressed. "It's all about distancing. And that's what actually drove down the numbers last spring," he said.

"We really did create a lot of distancing and until we do that, we're going to have an impossible time driving this virus down to a level which then we can test and trace on a routine basis like other countries and open up our economy again safely."

Tightening measures

In Texas, Hidalgo County Judge Richard Cortez issued a shelter-at-home order for all residents following a sharp uptick in cases and hospitalizations. The order, which includes a curfew, travel limitations and facial covering requirements, comes as the county's hospitals have hit capacity, Cortez said.

"To care for the patients that are already with the virus, we need more personnel, and personnel meaning doctors, nurses, technicians, respiratory technicians," the judge told MSNBC's Rachel Maddow. "Oxygen, of course, it is a big shortage right now. It is extremely important for us to have the necessary supplies."

Tuesday on CNN's "New Day," Dr. Peter Hotez of the Baylor College of medicine, explained why southern states such as Texas and Florida are seeing increased deaths.

"We had 34 deaths in the last 24 hours in not a very large county, so South Texas is just getting hit incredibly hard," Hotez said. "The hospitals are overwhelmed."

He said the county and many of the victims are poor, Hispanic, and working in jobs deemed essential, so they have to be at work to support their families. "There are many stories across Texas and across the southern United States among Hispanic and Latinx communities just getting hammered, and we're not really getting a full accounting of this," Hotez said.

The US Navy said in a statement Friday it is deploying some 70 medical personnel to support civilian hospitals in Texas.

Texas Gov. Greg Abbott, who previously pushed for one of the most aggressive reopenings, has more recently emphasized the importance of masks. He issued a mandate on face coverings earlier this month but has said there will not be another lockdown.

White House coronavirus response coordinator Dr. Deborah Birx said Monday taking the right precautions could be nearly as powerful as another lockdown.

At least 27 states have now halted or rolled back reopening measures in response to cases.

In Phoenix early Tuesday, people waited in long lines in their cars for tests.

In California, the governor shut down indoor operations for restaurants, movie theaters, wineries and closed down bars last week. Thirty counties on the state's watch list were required to close indoor operations for fitness centers, salons and places of worship.

The governor's office said Monday hair salons and barbershops in 33 counties could reopen outside. That's as Los Angeles County broke its record for daily hospitalizations for the fourth time in a week, said Dr. Barbara Ferrer, the county's public health director.

Governor says children are 'going to get over it'

City of Miami summer camps will close this week after at least three children contracted Covid-19, Mayor Francis Suarez announced during a press conference Tuesday. The closure will be effective this week.

States are now deciding what will happen next month, when students are slated to return to class. Many districts throughout the country have already announced they are beginning the year with online instruction.

President Donald Trump has said he's pressuring governors to reopen classrooms.

But on Tuesday, US Surgeon General Dr. Jerome Adams said the country needs to lower the transmission rate to reopen schools.

Speaking on "CBS This Morning," Adams said, "The biggest determinant of whether or not we can go back to school actually has little to nothing to do with the actual schools -- it's your background transmission rate."

Adams added that lowering the transmission rate will also help keep safe teachers and the adults living with school-age children. "We know the risk is low to the actual students. But we know they can transmit to others. ... We need to take measures to make sure we protect those who are vulnerable either because they are older or they have chronic medical conditions."

In Missouri, Gov. Mike Parson said Monday the state has to move forward with sending children back, saying the students are the "least likely to have a problem" if they contract the coronavirus.

"And if they do get Covid-19, which they will -- and they will when they go to school -- they're not going to the hospitals. They're not going to have to sit in doctor's offices. They're going to go home and they're going to get over it," he said on a radio interview.

While the US Centers for Disease Control and Prevention is still studying the role children play in transmission, the agency recommends children socially distance at 6 feet apart from people they don't live with and anyone 2 years and older wear masks in public when socially distancing is difficult.

Three vaccine trials offer hope

Evidence showed the vaccines can produce immune responses that would be expected to protect people against infection and all appeared to be safe.

The results were promising, researchers say, but large-scale trials are needed to determine whether the vaccines protect against the virus.