By Betty Yu

SAN FRANCISCO (KPIX) – A San Francisco epidemiologist says wearing masks is the most effective way Californians can stop the spread of coronavirus and get back on track to reopen.

California just surpassed 400,000 coronavirus cases on Tuesday. While that number is just behind New York’s total, California has far fewer cases per 100,000 residents.

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The state’s health secretary says unfortunately, California’s reopening has been treated as a green light by many to resume normal life and he will not hesitate to tighten restrictions if hospitalizations and deaths continue to rise.

“If the data trends turn to such a place where we aren’t confident we will get there, there will be potential for further dimming in parts of the state. Certainly in those counties we are monitoring closely,” said Health and Human Services Agency secretary Dr. Mark Ghaly.

The wait time for an appointment at the Embarcadero testing site has stretched even longer, to at least two weeks, as the number of cases grows beyond 5,300, in San Francisco.

California’s positivity and hospitalization rates are also trending upward over the last two weeks.

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State data shows the 7-day average for the number of new cases is 9,189 per day. The 7-day average from the week prior was 8,382.

“I think it’s inevitable that we’re seeing more cases, I wouldn’t have expected to see this many cases, but there is a feeling of inevitability to it. The solution is really, really, really simple, which is to wear masks when you go out,” said UCSF epidemiologist Dr. George Rutherford.

Rutherford says wearing a simple cloth mask cuts down the risk of transmission by 96 percent.

“In Southern California, which opened up earlier than the Bay Area, I think they opened up too early and got out of control,” said Dr. Rutherford. “Here in a handful of counties, some of the counties, it got out of control. But remember, we’ve had some nursing home outbreaks, we’ve had a massive outbreak at San Quentin.”

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Ghaly also said it could be more than a month before we see the real impact of the Governor Newsom’s recent rollback on reopening, and cases start to decline.