CDC COVID risk map highlights areas of high transmission in Bay Area staff KABC logo
Tuesday, August 3, 2021
Here are the Bay Area cities with the lowest vaccination rates
Experts say unvaccinated neighborhoods across the Bay Area are driving most of the transmission fueling our fourth COVID-19 surge.

SAN FRANCISCO -- The CDC released new guidelines that people wear masks indoors, regardless of vaccination status, in regions facing "high" or "substantial" COVID-19 transmission.

But what constitutes as "high" or "substantial?" And what parts of the United States and more specifically, the Bay Area, are seeing these high rates of COVID-19?

RELATED: Indoor mask mandate to take effect at midnight in 7 Bay Area counties

Along with the new guidelines, the CDC released a map showing which areas are experiencing surging COVID rates. In Bay Area, Alameda, Contra Costa, Napa, Marin, San Francisco Solano and Sonoma counties are all currently listed by the CDC as having "high" transmission rates, while Santa Clara and San Mateo counties are "substantial."

CDC COVID-19 Transmission Map by County

Click on a county below for more information, or search for a county in the table.

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Cases are rising across the United States as concerns around the delta variant grow. According to an internal document from the CDC, this variant appears to cause more severe illness and spreads as easily as chickenpox, with each infected person, on average, infecting eight or nine others. The original lineage was about as transmissible as the common cold, with each infected person passing the virus to about two other people on average.

VACCINE TRACKER: How California is doing, when you can get a coronavirus vaccine

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