(CNN) -- With a handful of states reopening parts of their economies, a coronavirus model routinely cited by the White House warns that no state should be opening before May 1.
South Carolina and Georgia, which are leading the pack to get their economic engines humming again this week, should not open until June 5 and June 19, respectively, according to the model maintained by the Institute for Health Metrics and Evaluation at the University of Washington. It was updated Tuesday.
Montana has the best forecast at May 1, while the only other states that should open by May 10, the model says, are Alaska, Hawaii, North Carolina, Vermont and West Virginia. North Carolina is the only of the six states with more than 1,000 cases, as of Wednesday afternoon.
About half the states in the country should remain closed until May 25 or later, with Arizona (June 23), South Dakota (June 25), Iowa (June 26), Nebraska (June 30) and North Dakota (July 12) rounding out the bottom of the list.
The reopening dates are based on an assumption that states will have other measures in place -- aggressive testing, contact tracing, isolation, limits on the size of gatherings -- to prevent a resurgence of the virus.
The IHME model relies on a conservative threshold of one infection per 1 million people, which is the level of infection each state could conceivably manage using containment strategies, such as widespread testing, contact tracing and isolation of new cases, according to an explanation of the model.
While the model has been influential, it is one of many, and the IHME has warned against relying too heavily on its projections.
"If I were a governor of a state, I would certainly not make a decision based just on our model," IHME Director Dr. Christopher Murray said in a virtual news briefing last week.
Another IHME model offered more grim news, as the projected US death toll by August jumped 10%, to 66,000.
The change came as states began updating their death tallies, adding residents of nursing homes whom officials are now counting as presumptive positives, Murray said Tuesday.
Experts to states: Slow down
As the numbers grow, the timeline for relaxing social distancing measures should be slowed down, Murray said.
Murray's team was taken aback when Georgia, which still has a high number of infections, announced it would soon ease restrictions, he said. Gov. Brian Kemp has said his state is prepared to handle an uptick in cases as businesses begin reopening Friday.
"If people start to go back to normal social interaction or even progressively go back, the risk of transmission will go up ... and then you go back to the sort of exponential rise that was happening before we put in social distancing," Murray told CNN. "The risk is very great for resurgence from these early openings."
That's as the US Centers for Disease Control and Prevention director gave an ominous forecast of a possible second wave of the virus in the winter.
"There's a possibility that the assault of the virus on our nation next winter will actually be even more difficult than the one we just went through," Robert Redfield told The Washington Post. "We're going to have the flu epidemic and the coronavirus epidemic at the same time."
The US has recorded more than 839,000 infections and at least 46,000 deaths.
News emerged Wednesday that the first death in the nation -- previously believed to the February 29 death of a patient in Kirkland, Washington -- actually came February 6 in Santa Clara County, California.
California is first state to recommend testing for asymptomatic people
To safely move forward, experts have emphasized the country should be able to track, trace and isolate cases.
The spread is something health officials all over California are trying to tackle, now recommending coronavirus testing for asymptomatic people who live or work in high-risk environments such as nursing homes or hospitals.
The new guidelines from the state's health department were announced in a Sunday memo. They make California the first state in the nation to broaden its guidelines for testing to include those without symptoms, state health officials told CNN.
The CDC previously advised testing high-risk patients and health care workers who have symptoms, a California Department of Public Health spokesperson said.
California is averaging 14,500 coronavirus tests a day, Gov. Gavin Newsom said Tuesday, calling the number "still inadequate." The state has a long way to go before it can attempt to reopen, he said.
The US has so far conducted 4 million tests
In two plans for reopening society, economists and public health experts say millions of tests should be conducted each week before restrictions can be lifted.
One report estimates at least 3,000,000 and up to 30 million tests should be conducted weekly, while the other says the US should be conducting 20 million tests each day.
So far, the country has performed about 4 million tests. While federal officials tout the country's testing capacity, some state leaders -- including Illinois Gov. J.B. Pritzker -- have reported that while they may have the necessary machines, they lack the materials and staff to run them.
A test that was approved by the US Food and Drug Administration may mean Americans can mail in their results. The test would allow patients to collect their samples using an at-home test kit and then mail it into the lab for testing, the FDA said Tuesday.
In most states, the test could be available within weeks to patients with a doctor's order, the agency said, and FDA Commissioner Dr. Stephen Hahn told "CBS This Morning" that may mean the country "could double the number of tests that are done in a very short period of time."
States are grappling with how to move forward
Despite the questions surrounding tests, many US governors and mayors have turned their attention to reopening their economies.
In a startling interview on CNN, Las Vegas Mayor Carolyn Goodman said the city's businesses should reopen, but she refused to provide any social distancing guidelines on how to do so safely.
"I am not a private owner. That's the competition in this country. The free enterprise and to be able to make sure that what you offer the public meets the needs of the public," Goodman, an independent, told CNN's Anderson Cooper on Wednesday.
"Right now, we're in a crisis health-wise, and so for a restaurant to be open or a small boutique to be open, they better figure it out. That's their job. That's not the mayor's job."
Last week, the federal government said in order to launch the first of three phases of reopening, states should wait to see a 14-day decline in cases.
South Carolina and Georgia have hit neither milestone but announced they'll be easing restrictions.
Atlanta is exploring whether the city has legal grounds for putting different orders in place than what Kemp has announced, Mayor Keisha Lance Bottoms told CNN on Tuesday
"I am at a loss as to what the governor is basing this decision on," she said.
In Boston, officials have plenty of work to do to contain the virus, Mayor Marty Walsh told CNN, and it's "pretty scary" to think some states are considering reopening.
South Carolina Gov. Henry McMaster announced certain stores are allowed to open at 20% capacity, and beaches can reopen, too, but schools will remain closed for the rest of the school year.
In Tennessee, Gov. Bill Lee announced most businesses across the state will be able to reopen May 1, once the state's stay-at-home order has expired -- but hinted some may be able to open sooner.
California's governor was not optimistic about the timeline for the return to normalcy.
"No one wants to share that information more with you than I do," Newsom said at the start of his daily press conference. But he stopped short with the words, "There is no date."
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