(CNN) On a day several more states, including Florida, told most of their residents to stay at home, the number of US coronavirus cases skyrocketed past 200,000 on Wednesday.
The news comes while debate revs up on whether all Americans should be wearing a mask.
As of Wednesday afternoon, more than 210,000 people in the United States have been infected, and at least 4,703 have died. The number of fatality reports again reached a new daily high, with more than 900 reported.
One of the deaths was a 6-week old in Connecticut, Gov. Ned Lamont said.
More data showing people without symptoms are fueling the spread has top US officials rethinking whether the general public should be wearing masks. But the World Health Organization, while it says it is reviewing its advice, tells people there is no need to keep your mouth covered if you are not a patient or health worker.
Concerning new data from Iceland shows 50% of those who tested positive said they were asymptomatic.
In the US, an estimated 25% of coronavirus carriers have no symptoms, said the director of the Centers for Disease Control and Prevention.
"Information that we have pretty much confirmed now is that a significant number of individuals that are infected actually remain asymptomatic. That may be as many as 25%," CDC Director Dr. Robert Redfield told NPR.
To prevent further spread, the top infectious disease expert in the US says health officials are reconsidering guidance on face masks.
Dr. Anthony Fauci said he would "lean towards" recommending that the general public wear face masks "if we do not have the problem of taking away masks from the health care workers who need them."
"We're not there yet, but I think we're close to coming to some determination," Fauci said.
If federal officials recommend widespread use of face masks, it would be a stark reversal from recommendations by the World Health Organization and the CDC, who have said face masks should be worn only by health care workers, those who are sick, and those who are taking care of someone sick.
The organization is "continuing to study the evidence" about whether the general public should use masks during the coronavirus pandemic, WHO Director-General Tedros Adhanom Ghebreyesus said during a media briefing in Geneva, Switzerland, on Wednesday.
The WHO recommends the masks for sick people and caregivers, he said.
"This is still a very new virus, and we are learning all the time. As the pandemic evolves, so does the evidence, and so does our advice," he said.
US Surgeon General Dr. Jerome Adams had consistently recommended the public not wear masks, saying they can cause more harm than good.
But this week, new information about asymptomatic spread could change public guidelines, Adams said.
A major argument against the widespread use of masks is that health care workers don't have enough.
"We have a massive global shortage," Dr. Mike Ryan, executive director of the WHO health emergencies program, said. "Right now, the people most at risk from this virus are frontline health workers who are exposed to the virus every second of every day. The thought of them not having masks is horrific."
In many cities, doctors and nurses are falling sick with or dying from coronavirus. This is doubly tragic because fewer health care workers are able to take care of the public.
So some people are making their own masks. JOANN Fabrics and Craft Stores released a video tutorial on how to make face masks.
Nearly 90% of the US population now lives in areas that have stay-at-home orders, according to a CNN count based on various state, county and city orders.
Some say that's not enough and are calling for a national shelter-in-place order, especially because the deadly virus is twice as contagious as the flu.
Florida, with 21 million residents and a large senior citizen population, joined the list Wednesday. Gov. Ron DeSantis issued an executive order directing seniors and people with underlying medical conditions to stay home. All Floridians must limit their movements, he wrote. The order takes effect early Friday.
Governors in Georgia and Mississippi also issued orders Wednesday.
While 12 states have not issued stay-at-home mandates, President Donald Trump said he doesn't think a national order is necessary.
"States are different and I understand that the governor of Florida, great governor, Ron DeSantis, issued one today and that's good, that's great. But there are some states that are different. There are some states that don't have much of a problem," Trump said at a news conference on the US coronavirus response.
Health officials say social distancing efforts seem to be paying off, including in Washington state's King County -- the country's first coronavirus epicenter.
"We are looking at reductions in person-to-person contact that have progressively improved and have led us to a point where we are making a very positive impact," said Dr. Jeff Duchin, the public health officer for Seattle and King County.
In hard-hit New York, a CNN analysis shows the day-to-day average of case increases in the past week was 17% -- a major decrease from 58% for the previous seven-day period.
And a large-scale study found that early interventions, such as social distancing and severe restrictions on people's movement, have already saved tens of thousands of lives across Europe.
Scientists at imperial College London studied interventions in 11 European countries and concluded that they "have together had a substantial impact on transmission."
The researchers estimate as of March 31, "interventions across all 11 countries will have averted 59,000 deaths."
You asked, we answered: Your top coronavirus questions
The calls for help with vital equipment for treating patients continue. One hospital CEO even went to Twitter on Wednesday to ask Tesla head Elon Musk whether he could supply ventilators.
"We are down to one critical care ventilator," the message from the account of Mark Geller said about Montefiore Nyack Hospital.
Hospital spokeswoman Lauren Malone told CNN in an email that Geller "decided it was worth sending a message" to the Tesla head.
"We have not heard back from Mr. Musk, but perhaps we will be lucky enough to receive ventilators," Malone said.
The hospital was able to obtain 10 ventilators from another source, Malone said.
CNN has reached out to Tesla for comment.
Colorado Gov. Jared Polis said the state has been talking to factory owners from China and other countries, trying to buy equipment.
"We know that not having gotten nearly enough from the federal government, we have really taken it upon ourselves as a state to engage in the purchasing of medical equipment," he said.
Polis said the state doesn't have the hospital beds, ICU units, ventilators and personal protection equipment to treat all potential patients. He said they have ordered some supplies, but, for instance, need to make sure the masks they bought aren't counterfeits.
Why worry about coronavirus when the flu has killed more people?
CORRECTION: This story has been updated with the correct percentage of Americans under a stay-at-home order.