'Worst is yet to come': SF public health director says virus will escalate in 1-2 weeks

Fisherman's Wharf and surrounding streets are seen empty in San Francisco California on March 17, 2020. - Millions of San Francisco area residents last Monday were ordered to stay home to slow the spread of the deadly coronavirus as part of a lockdown effort covering a section of California including Silicon Valley. (Photo by Josh Edelson / AFP) (Photo by JOSH EDELSON/AFP via Getty Images) less Fisherman's Wharf and surrounding streets are seen empty in San Francisco California on March 17, 2020. - Millions of San Francisco area residents last Monday were ordered to stay home to slow the spread of the ... more Photo: JOSH EDELSON/AFP Via Getty Images Photo: JOSH EDELSON/AFP Via Getty Images Image 1 of / 50 Caption Close 'Worst is yet to come': SF public health director says virus will escalate in 1-2 weeks 1 / 50 Back to Gallery

It's a question on the minds of San Francisco residents: When will coronavirus cases in the city peak?

At a Monday afternoon press conference, San Francisco Public Health Chief Dr. Grant Colfax suggested the peak may be just around the corner, saying the number of patients infected with COVID-19 in the city will escalate in a week or two.

"I am sad to have to say the worst is yet to come," Colfax said. "Every community where the virus has taken hold has seen a surge in coronavirus patients who need to be hospitalized. We expect that to happen in San Francisco in a week or two or perhaps less."

UC Berkeley infectious disease professor Dr. John Swartzberg said he agrees with the timeframe presented by Colfax.

"To understand what he's saying, picture a graph that's slowly going up and up and up and then suddenly it turns north. We're just on the part of that curve where it's going to start going up really fast," Swartzberg said.

UCSF professor of epidemiology Dr. Jeffrey Martin said what we’ll see in the next week or two really represents transmission that occurred in the past one to three weeks, roughly between Feb. 14 and the first week of March.

"Most of that period was when we were not in an intensive social distancing mode," Martin said. "It was spreading in an invisible way in early March. That is what we will see in the next 10 to 14 days. People shouldn’t be confused by that, however, and thinking that what we have been doing hasn’t been working."

On March 5, San Francisco had two coronavirus cases. As of Monday afternoon, the city had 131 — but there are likely many more cases due to the limited number of people who have been tested.

Swartzberg said we're at a point "where there's enough people infected who can infect enough other people to cause a steep rise in the number of cases."

He added: "We'll see the numbers going up because there's more spread. They'll also go up because we're testing more, not a lot more, but more. The numbers will be raised a bit artificially as well due to better identification."

What does a surge in patients look like? Swartzberg said one of the biggest impacts will be that hospitals will fill up.

At the Monday press conference, San Francisco officials said they're preparing for the surge and have hired 82 new nurses. The state has provided 1 million masks for S.F.'s front line health care workers and first responders. Facebook has donated an additional 100,000 masks and 400,000 gloves.

If the number of cases starts to escalate in a week or two, then when will San Francisco hit the peak?

"It depends on how carefully we shelter in place," said Swartzberg. "If more of us start to behave responsibly then we're going to see that peak come sooner, and the curve not rise as fast. It's not like we don't have precedent for that. We have China, Taiwan, Singapore and South Korea as places that took extreme measures."

Martin adds that he suspects we could hit a peak in 10 to 14 days. "A peak means it goes down," he said. "I would expect in 10 to 14 days if people are complying, then things would indeed begin to go down."

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Amy Graff is a digital editor with SFGATE. Email her: agraff@sfgate.com.