Why is the number of SF COVID cases so much higher now than in the US?

Earlier this spring, the city’s confirmed new cases rose above those in the US. On May 3, the number of cases in San Francisco doubled that in the US. As of May 10, the national daily number of cases was about 23 new cases per 100,000 people, while in SF the rate was 42 per 100,000, according to New York Times data analyzed by The Chronicle.

Peter Chin-Hong, an infectious disease expert at UCSF, said the current high rates of disease in San Francisco are likely due to the city’s relative protection from the disease over the past two years, coupled with city dwellers who take more risks as local pandemic-era restrictions and messages disappear.

“You can only protect yourself for so long,” Chin-Hong said. “If people are tired or tired for various reasons, and you’re moving, you’re at increased risk.”

Because San Francisco has done such a good job of preventing its residents from becoming infected during most of the pandemic, he explained that fewer San Franciscans have been given immunity to previous illnesses, so they are generally more likely to get sick at this point. to contract COVID-19 than other residents of other cities.

And while a higher proportion of San Franciscans are vaccinated than the US as a whole, COVID-19 vaccines have become less effective at preventing infection because the coronavirus strains have mutated, he added.

While a COVID-19 surge is never good news, Chin-Hong said the rise in cases so far has not resulted in a large corresponding increase in hospitalizations — likely because of the number of San Franciscans being vaccinated and encouraged. . † Vaccines may have become less effective at protecting infection as the virus mutates, but they are still excellent at preventing serious illness and death.

“If I had to choose one evil over another, I would definitely pick people who don’t really get sick,” Chin-Hong said.

Hospital admissions in San Francisco have increased since April, but are still well below the level of previous waves, according to city data. The city’s average hospitalization rate as of May 9 was 6.4 per 100,000 people, higher than the current US rate of 4.5 per 100,000, but a narrower gap than what would be expected given the difference in the number of cases.

A similar phenomenon is paying off in San Francisco at the neighborhood level: Right now, for the first time since the start of the pandemic, wealthier neighborhoods in the city have seen a sustained period of higher rates of illness than those with lower incomes.

As The Chronicle previously reported, this is likely because previous waves, most notably the January omicron tidal wave, gave lower-income neighborhoods an immunity boost that helps them combat this current wave.

Leave a Comment