A few factors could be at play. The virus may have already reached the most susceptible people currently at high risk. Indoor mask mandates and growing public awareness may be slowing transmission. People may be erring on the side of caution and changing their behavior. Suddenly the beach or an outdoor patio is more appealing than the movie theater or a packed dance club.
“Past surges here and elsewhere often peak after around 2 months,” said Moss. “We don’t believe vaccine uptake has increased enough in the last few weeks to drive a big change, but it is difficult to know for certain.”
Overall the current wave of cases is comparable to the 2020 summer surge, but not nearly as dire as last winter. Relatively high vaccine rates are insulating the Bay Area. In all nine Bay Area counties at least 60% of residents have at least one shot, in most counties the rate is above 70%.
“The people who weren't vaccinated are getting COVID at a much higher rate,” said Dr. Peter Chin-Hong, an UCSF infectious disease expert. “And then that leads to a combination of natural immunity plus vaccination, which really increases the force field against any new infections coming into the community.”
However Chin-Hong warns this phenomenon could be a temporary reprieve because doctors do not know how long natural immunity from an infection will last.
“We don't know how durable or how reliable that immunity will be on an individual level compared to a vaccination,” he said. “And it may not work against future variants.”
Yet clouds loom over this potential good news. Across the state 7,063 patients are hospitalized with a confirmed case of COVID-19. That tally has nearly doubled in the past two weeks, and still appears to be rising.
“Cases are not increasing as rapidly as we saw were earlier on,” said Chin-Hong. “Yet in the [UCSF] hospitals, we're still seeing about 8 times as many patients compared to the time of [the economy’s] reopening in June.”
In a best case scenario Chin-Hong predicts case counts will begin decreasing by the end of August, and then hospitalizations will follow in mid September.
The wild card is opening schools. Even if outbreaks are not sparked within the classroom, both students and parents will be traveling around a lot more as they come and go from campuses and after-school activities. More interactions could lead to increased transmission. Plus many schools and universities are ramping up testing, which could lead to an uptick in asymptomatic cases in people who would not otherwise be tested.
It’s a bit of a wait and see situation. COVID-19 is reliably unpredictable.
Chin-Hong hopes delta is both humbling and motivating for those who are still not vaccinated. He says the thought of a super variant like delta or worse keeps him up at night.
“These are not the end of the story because COVID is still raging,” said Chin-Hong. There's still a lot of susceptible noses and mouths that the virus is trying to exploit.”
Unvaccinated Californians can go to myturn.ca.gov or call (833) 422-4255 to schedule their appointment or go to myturn.ca.gov/clinic to find a walk-in clinic in their county.