Fewer people traveled for Thanksgiving this year, but the holiday is still expected to contribute to a major surge of COVID-19 cases in San Francisco, experts say.
Though The City is already in the midst of a spike in new cases, the holiday’s impact won’t likely be seen until two to four weeks later, according Dr. Peter Chin-Hong, an infectious disease expert at the University of California San Francisco.
As of Oct. 22, The City averaged 34 daily new cases. Now, it’s looking at 140. Hospitalizations have followed suit, doubling in just 10 days, from 40 on Nov. 18 to 87 on Nov. 28.
That number is likely to increase in the coming weeks.
“From a biological perspective, you’re bringing different noses and mouths together from different places and in big crowds,” Chin-Hong said of Thanksgiving gatherings that could generate what he calls “a surge on top of a surge.”
Plus, the airborne virus is more readily spread when people are highly emotive, whether that’s with laughter, talking loudly or even yelling out of frustration, he said, all of which are not uncommon during the emotionally charged holiday season.
Although San Francisco International Airport recorded a roughly 75 percent drop in passenger volumes during the week of Thanksgiving this year as compared to last, officials say it’s likely that many people opted to drive to their holiday celebrations or gather locally, both of which still buck the public health guidance to stay home and avoid indoor groups outside the household.
From Nov. 22 to Nov. 28, which includes the bulk of Thanksgiving week, 242,337 cars crossed the Golden Gate Bridge, recent data shows. That’s a 26 percent drop compared to the same period last year, but it’s still the best week relative to last year since shelter-in-place has started, indicating more people were crossing the bridge by car than usual for this year.
While personal cars do represent a safer mode of transportation than a shared vehicle, train or plane, what matters more than the method of travel is the behavior associated with it, such as family gatherings, overnight stays in hotel, gas stops or even grabbing food at a local eatery.
“In March and April, we were thinking about the risk of transportation itself. But it’s the things you do along the way that increase the risk,” Chin-Hong said.
With Christmas less than one month away, local officials are trying to discourage further gatherings and travel.
Anyone who decides to travel in the future could be subject to a mandatory quarantine, Mayor London Breed and Dr. Grant Colfax, head of the Department of Public Health, told the public in a press conference Tuesday.
San Francisco joined the ranks of counties in the state’s purple tier last week, forcing the prompt shutdown of many indoor establishments, reducing capacity at others and imposing a 10 p.m. curfew citywide on non-essential activities.
More restrictions, such as caps on the size of outdoor gatherings or the aforementioned traveler quarantine, could come this week, Breed and Colfax cautioned.
UCSF has already seen nearly three times the number of hospitalizations as just one month ago, according to Chin-Hong, who likened the steady climb of COVID-19 cases to a roller coaster that keeps going up.
“When the roller coaster falls down, you’re just going to fall off the cliff, and that’s ultimately not having enough beds for people,” he said. “That’s what we’re hoping won’t happen.”
The best thing to do is to stay put, but for those who absolutely have to travel, Chin-Fong said they should adhere to the 14-day self-quarantine guidelines as much as possible, and aim to get a test no sooner than three days after returning to San Francisco, as that’s really the earliest the test would catch the virus.