Coronavirus cases are ticking up across California after a month of relative stability, but Bay Area health officials say they’re encouraged by low rates of COVID hospitalizations — particularly for patients needing intensive care, which are at their lowest levels since the pandemic began — and they’re not bracing for another surge or expecting an imminent need to restore preventive measures like mask mandates.
California is not yet experiencing a swell of cases similar to what has been reported across parts of the Northeastern U.S., where large outbreaks have infected high-profile policymakers and Broadway stars. With the highly infectious BA.2 variant of the coronavirus taking hold across the country and case reports creeping up in many regions, federal health officials on Wednesday extended the mask mandate for all public transportation that was set to expire next week. And earlier this week, Philadelphia became the first city in the country to reinstate a local indoor mask mandate in response to rising cases.
But Bay Area officials say they are shifting away from relying primarily on case reports in shaping their local COVID response, and expect to be less reactive to day-to-day ups and downs in the numbers. Instead, they’re keeping an eye on trends over weeks, and using an array of surveillance systems to help them understand when a surge may be starting — and whether it’s likely to cause a large number of people to become severely ill or need hospital care.
At the moment, though they’re keeping a watchful eye on the COVID situation in the Northeast and locally, they’re feeling confident that the Bay Area is well situated to weather BA.2.
“Overall things are still very favorable,” said Dr. Nicholas Moss, the Alameda County health officer. “We remain at relatively low case rates and relatively low hospitalizations. But we are off our low point for cases, just a little bit. It’s just a reminder that things will probably continue to be dynamic.”
Tracking the coronavirus — a critical tool for controlling spread of disease since the pandemic began in early 2020 — has undergone a subtle but important shift over the past couple of months, as California and the rest of the U.S. develop strategies for coexisting with a virus that is unlikely to ever go away completely. Daily case reports had been a driving metric for everything from requiring masks to shutting down certain activities.
But “it’s been a long time since we adjusted COVID strategy on a day-to-day basis,” Moss said.
Case reports, which were never able to capture a complete picture of the full spread of disease in a community, have become even more imprecise with increasing reliance on home testing that is not reported to public health departments. Meanwhile, high rates of immunity — due to vaccination and previous infection or both — mean that far fewer people are becoming seriously ill, and case counts don’t translate as directly to hospitalizations as they once did.
In February, the Centers for Disease Control and Prevention unveiled new metrics for determining the threat posed by COVID in communities, relying far less on local cases and more on hospitalizations; as of this week, every state was in the “low” threat category, even in regions that are reporting upticks. In California, the state public health department shifted this month to publicly reporting case numbers twice a week instead of five times.
Bay Area health officials said that as long as hospitalizations remain low, they don’t expect to put in place more public health restrictions unless they see some sign that more people are becoming very sick.
“Our cases have been going up steadily over the last 10 days or two weeks, but they haven’t sharply increased,” said Dr. Grant Colfax, head of the San Francisco Department of Public Health, which has reported a more-than-50% increase in daily cases over the past month — albeit from a low base — along with a rise in the percentage of tests coming up positive, from 2.4% a month ago to 4.4%. “We’re not seeing what we saw with the omicron surge.”
Colfax said that bringing back a local mask mandate is “not on the table” at the moment, though it will remain an option for the foreseeable future if there’s another large surge. In fact, San Francisco health officials no longer recommend masking for most situations, though people should continue to wear them if they prefer, Colfax said.
Marin County may move toward reporting case data less frequently, said Dr. Matt Willis, the health officer. That’s in part because cases are so low that a single outbreak can throw off the daily counts, making it appear as though cases are spiking across the community. He experienced that issue this week when dozens of eighth-grade students returned from class trips to Washington, D.C., with coronavirus infections. Marin has been reporting 20 to 30 cases a day for about the past month, so adding 50 cases overnight might make the situation look dire.
“I get concerned sometimes that if people see a spike like that on a given day that they might incorrectly assume that we’re seeing a surge in cases,” Willis said. “We need to realize, that we’re going to see sawtoothing, ebbs and flow of the virus, and we don’t want to overreact.”
Still, some health experts have expressed concern that relying too heavily on longer-term trends or on hospitalizations could delay efforts to control the virus before another surge takes hold.
Dr. Abraar Karan, an infectious disease expert at Stanford, said he’s still wearing a mask in many public spaces. He had COVID earlier this year, in the thick of the omicron surge, and he’s eager to do all that he can to prevent reinfection. He worries that others will get sick in the coming weeks if they assume that the risk is low in their community and don’t take precautions.
“When you have rapid spread, it’s exponential. If you say let’s just see what happens every few weeks, then eventually when you have a problem it’s too late to prevent it,” Karan said. “It could be next week or two weeks from now they start telling everyone to wear masks. Why would I wait for that? By the time they say that I may already be infected.”
Erin Allday is a San Francisco Chronicle staff writer. Email: eallday@sfchronicle.com Twitter: @erinallday
2022-04-13 22:45:28