Three factors that could be contributing to San Francisco's surge in COVID cases

Concern over continuing spread of the COVID-19 Delta variant is reaching even the highly vaccinated city of San Francisco. According to the San Francisco Department Of Public Health, 83% of eligible residents ages 12 and up have had at least one dose of a COVID vaccine. 

That's 75% of San Francisco's total population, which is higher than the state and federal levels. Still, COVID-19 is spreading quickly.  

This week, the number of new COVID-19 cases increased 81% from the previous week, according to the California Data Coalition.

"We've got a virus circulating now the Delta variable that's twice as transmissible is the variant that caused that terrible time we had in December in January," said Dr. John Swartzberg, an infectious disease expert with UC Berkeley School of Public Health.

Dr. John Swartzberg says along with the Delta variant, the surge in cases is also partly due to the state's reopening on June 15th.

"A lot of people just thought this pandemic was over, interacting like that. And doing this, the kinds of things that put them at risk for getting infected," said Swartzberg.

And even with the high vaccination rate, children under 12 still are not eligible for the vaccine. San Francisco also is a destination spot for visitors from less vaccinated locations in California and nationwide.

"We still have an awful lot of people who are not vaccinated, so there's plenty of places where this virus can go and plenty of people that it can infect," said Swartzberg.

Hospitalization rates are also increasing, but the great majority of patients are unvaccinated

About 5.8 people per 100,000 fully vaccinated residents in San Francisco are coming down with COVID-19. Swartzberg says for now, that small percentage is in line with expectations.

"It is in line with it but it's at the upper end of in line with it, we need to we need a few more weeks to see if we're getting more breakthrough cases with delta or not," said Swartzberg, "The most important statistic is really the hospitalizations and deaths in there we're just not seeing it most people were vaccinated."

A new poll released Friday by the Associated Press found among the Americans who still have not been vaccinated 80% said they probably will not get the COVID vaccine. 64% of those unvaccinated do not believe the shots are effective against the coronavirus variants.