Will California see another surge of the coronavirus?
Some medical experts say they are not expecting a fourth wave of COVID-19 cases
COVID-19 cases are starting to climb again across much of the U.S., prompting officials to warn of a possible fourth wave of the deadly virus even amid the vaccine rollout. Could California be headed for the same fate?
Infectious disease experts in the Bay Area say the Golden State may be well positioned to escape another surge — but things could change if too many unvaccinated people succumb to the allure of unsafe springtime gatherings.
“I don’t believe we’ll see a rise in California like in other parts of the country,” said George Lemp, an epidemiologist and former director of the HIV/AIDS Research Program at the University of California Office of the President.
There are a few reasons for Lemp’s optimism. The coronavirus is spreading slower in California right now than in almost ev
ery other state. He points to a decrease in new cases here across all age groups between the second half of February and the first half of March. Those 65 and older saw cases decline by roughly a third, while those in the 18-34 age group saw slightly more modest declines of about 26%.
“These trends may reflect the early impact of the vaccine distribution by age in California,” Lemp said.
Photos of rowdy spring breakers gathering unmasked in places like Miami Beach have prompted warnings to young people from public health officials about the need to continue distancing and other precautions. But, Lemp and others said, it’s not clear similar gatherings are happening here, where more stringent coronavirus rules remain in place.
Unlike anytime in the past when California has reopened with only mask and distance requirements and limited capacity at businesses, “we now are applying the protective veneer of vaccines,” said Monica Gandhi, an infectious disease expert at UC San Francisco.
“With roughly 30% of our population in California having received at least one dose of the vaccine and another 30% having some natural immunity,” she said, “we will not see a fourth surge in our state.”
California has its own variant of the original COVID-19 virus, but it appears to also be very susceptible to the vaccines, whereas different variants spreading more rapidly elsewhere in the U.S. may be a little more resistant.
Lemp also thinks the state may be closer to “herd immunity” than people realize — with a majority of the population now likely protected by either vaccines or natural immunity from previous infections. In New York and other places that were hit hard early on, some natural immunity may now be waning. But California was clobbered just a couple of months ago, meaning people who have recovered from the disease may have more robust antibody protection.
And vaccine access and supply are poised to expand rapidly in the coming weeks, Lemp said, so the state may get lucky in escaping a next surge. Californians 50 and up will be eligible for a shot on Thursday, with those 16 and up gaining access on April 15. The state is expecting to get significantly more vaccine in the coming weeks.
It’s clear the race is on. In a call with governors on Tuesday, Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, cited “concerning” national trends: The seven-day average of 65,789 new COVID-19 cases per day is up 19% from two weeks ago. In California, the average is down about 18% over the last two weeks to 2,605 cases.
John Swartzberg, clinical professor emeritus of infectious diseases and vaccinology at UC Berkeley, agrees that California “does have some things going for it that many states do not,” especially in the Bay Area where people tend to follow public health directives and where officials have mandated mask-wearing and other measures.
But, he pointed out, the decline in cases locally is flattening out.
“We are not an island,” he wrote in an email, adding that while Lemp’s calculations for March “look encouraging when compared with a month before, I am not optimistic about the forecast for the next month. I do not think California will have a surge; maybe not a swell. But, I bet the next four weeks will show a net increase.”
Daniel Shin, an infectious disease specialist at El Camino Health who saw one of the first known COVID-19 cases in the Bay Area more than a year ago, is even less optimistic that California’s troubles are behind us. He points out that air travel is up, meaning people from places with more spread and fewer restrictions can bring the virus with them.
“During this entire pandemic, the last 14 months, we have never been excluded from a surge that’s affected other parts of the U.S.,” Shin said. “I am concerned that it’ll eventually catch up to us.”
Shin thinks that while the vaccine rollout has helped mitigate the spread of the disease and contributed to a decline in the average age of his hospitalized patients, he’s worried younger people who aren’t vaccinated yet will get too comfortable with the idea that herd immunity is imminent and engage in risky behavior “that will actually drive the surge.”
In California, hospitalizations among those 80 and older have declined from more than 3,000 at the start of January to fewer than 200 by March 19, dropping markedly each week. While hospitalizations among those 18-29 in the state have fallen, they’ve dropped less significantly — from just shy of 700 in the beginning of January to slightly more than 200 in mid-March, holding steady in recent weeks. The week of March 19, hospitalizations among young people outnumbered hospitalizations among those 80 and up.
While the numbers in California might not look so worrisome now, Shin thinks people might be in for an unpleasant lesson in exponential growth.
“It doesn’t alarm people when something goes from two to four and four to eight. They just see numbers,” he said. “But for a scientist or epidemiologist, when they see a logarithmic rise in numbers, they know it’s eventually going to reach a point where it takes off.”