Shutting down indoor bars and getting almost everyone to wear masks in public is “really as good as shutting it down” and will help stop the surging coronavirus outbreaks across the country, a top White House health official said Thursday.

“We are all concerned about the increase in cases we are currently seeing throughout the country and as you know, more than 50% of those cases are occurring in four states: Arizona, Texas, Florida and California,” Assistant Secretary for Health admiral Brett Giroir told reporters on a conference call. “But we are seeing similar trends in multiple states primarily in the Sun Belt.”

“But the bottom line is, we know what to do to stop the current outbreak,” he added. “Now we have very, very good models that in the hot areas, these red zones that have high cases, that have high percentages increasing, it’s very, very important to really close indoor bars.”

He said that between 50% and 70% of new cases have been traced to a single bar in some areas and “secondary spread from that.” He added that the same concerns apply to indoor restaurants, as well, and they should be operating at 25% capacity. 

“Being indoors, in close quarters, over long periods of time, is just a recipe for spread,” he said, adding that outdoor seating for restaurants and bars is “probably really safe.”

In the “hot zones,” almost 90% of people should be wearing masks “when they’re interacting with other people” to bring the spread under control, he said. 

“If we have that degree of compliance with these simple measures, our models say that’s really as good as shutting it down,” he added. “These simple facts can really shut down the outbreak without completely shutting down your local area.”

The Centers for Disease Control and Prevention on Tuesday called on Americans to wear masks to help contain the spread of the virus. Director Dr. Robert Redfield told Dr. Howard Bauchner of the Journal of the American Medical Association in an interview Tuesday the U.S. could get its outbreak under control in one to two months if every American wore a mask. 

“The time is now,” Redfield said. “I think if we could get everybody to wear a mask right now I think in four, six, eight weeks we could bring this epidemic under control.”

Despite the rising number of new cases, Giroir said Thursday that the U.S. is “in a much different place today than we were in April.” He said the U.S. has more tools to combat Covid-19, such as better clinical treatment, therapuetics like remdesivir, steroids and convalescent plasma, and more widespread testing. Coronavirus researchers and public health specialists have been hopeful that these tools will mean a smaller portion of infected people will die than did in hard-hit areas in March and April. 

However, some of the benefits of those tools might be strained by the magnitude of the current outbreaks across the U.S. The country’s testing infrastructure, for example, is struggling to keep up with the demands of the expanding outbreaks. 

Quest Diagnostics and LabCorp, two of the largest diagnostic labs in the country, said earlier this week that the increased demand for testing is slowing their turnaround time. Quest said results for patients who are not “priority 1” now take more than seven days, which public health specialists say makes the tests almost useless to trace cases and isolate people who’ve been exposed.