COVID spreading fast in well-vaccinated California counties

Cases falling in counties with below-average vaccination

Vallejo Times-Herald, by John Woolfolk & Harriet Rowan, July 24, 2021

That doesn’t mean the vaccines don’t work — rates for infection and hospitalization remain vastly higher among the unvaccinated. So what’s going on? Experts point to two things: the extraordinary ease with which the virus’ now-dominant delta strain spreads, and the fact that no vaccine offers impenetrable protection.

“I am not so surprised that transmission rates are not neatly tracking immunization rates,” said Dr. Stephen Luby, a medical professor specializing in infectious diseases at Stanford University.

“There are a number of issues that contribute to transmission,” Luby said. “In high density urban settings, for example, even with a higher level of vaccine coverage, there can still be a lot of exposure to unvaccinated folks and potentially to folks who are vaccinated but are asymptomatically shedding the delta variant.”

The soaring case rates spurred action and pleas this past week from public health officials in the Bay Area and politicians in some of the most vaccine-resistant parts of the country. Health officials in Santa Clara, San Francisco and Contra Costa counties urged employers to require vaccinations for all workers. Senate Minority Leader Mitch McConnell implored the unvaccinated to get their shots and ignore “demonstrably bad advice,” while the Republican governor of Alabama — the least-vaccinated state in the country — said “it’s time to start blaming the unvaccinated folks” for the virus’s continued surge.

The delta variant, which devastated India in the spring, is highly contagious and has since spread globally and throughout the U.S. and California where it accounted for 82.8% of sequenced viral specimens as of Wednesday, up from 48.8% a month earlier.

There have been mixed reports about the vaccines’ effectiveness against the variant, most of which indicate they still offer broad protection, and case rates show the fully vaccinated remain well protected.

The California Department of Public Health reported Friday that between January 1 and July 14, 99% of the state’s cumulative cases have been among unvaccinated people. For the week of July 7-14, the average daily case rate per 100,000 among unvaccinated Californians was 13 while the rate for the vaccinated was 2, the CDPH said.

A similar picture emerges locally. In Contra Costa County, which reports case rates by vaccination status, the average rate per 100,000 among the unvaccinated was 27.8 on July 16 — six times the 4.5 rate reported in the vaccinated population. In Sonoma County, the rate was 15.1 among the unvaccinated, and 3.7 for the vaccinated.

But although the vaccines do a good job bolstering the body’s ability to fight infection, they aren’t impenetrable shields. Because vaccinated people are being exposed to higher levels of a more contagious variant circulating in densely populated urban areas, their chances for contracting one of the few vaccine “breakthrough” infections are greater.

“The best, most waterproof raincoat is protective, but not when it’s storming outside or you’re in the middle of a hurricane,” said Dr. Kirsten Bibbins-Domingo, a professor of epidemiology at UC San Francisco.

She and Luby added that some vaccinated people may be spreading the virus without knowing they have it while their bodies fight it off.

And since California’s June 15 reopening, when the state retired its face mask mandate and color-coded system of pandemic restrictions based on case rates, people have been venturing out more without masks to stores, restaurants and events that no longer have pandemic crowd limits. Although many people still use masks in places like the Bay Area, that can only do so much.

“It’s definitely depressing to see how quickly things turned,” Bibbins-Domingo said. “But the threat of the virus has always been there. Delta is a highly transmissible variant, something we have to respect. Even with some of the masking, we’re moving around a lot, we’re going along with our usual patterns of behavior. Put those together and you can quickly see, even though we’re wearing masks, we have vaccination, there’s no margin for error any more.”

While vaccination levels are relatively high in California and the big cities where the virus is spreading, there still are many who haven’t had or can’t get the shots.

According to figures from the Centers for Disease Control and Prevention, California’s 61.1% vaccination rate of those 12 and older compares favorably to the 55.3% in Florida and 53% in Texas, and isn’t far behind New York’s 65.4%. But many, including kids under 12 and people with medical issues, can’t get the shots. Just over half California’s nearly 40 million people — 52.1% — are fully immunized.

“Once you put in the full population denominator, it’s not as high as we think,” Bibbins-Domingo said.

The rapidly worsening pandemic picture — coming at a time when many hoped the virus would be a fading memory — has led many health experts to call on federal and state authorities to reverse course and impose more face mask requirements and restrictions.

Both the CDC and California Department of Public Health have maintained that the answer remains simply getting more people vaccinated. But resistance among some people will be hard to overcome.

For now, many local health officials have been stepping in, urging people to resume wearing masks indoors, where the virus spreads more easily, regardless of vaccination, and employers to require that their workers get the shots. Some businesses, including San Francisco bar owners, are considering requiring their customers provide proof of vaccination, fearing a return of the pandemic restrictions that closed them down entirely.

Health experts like Bibbins-Domingo support all of that, and sympathize with the messaging dilemma facing public health officials.

“The challenge in public health communication is we ultimately do want more people to be vaccinated,” Bibbins-Domingo said. “And the concern is communicating that we also need to wear a mask right now will then dilute the message that we need to be vaccinated. The challenge is that both things are true.”