California continues to have the lowest levels of coronavirus transmission in the country, according to the U.S. Centers for Disease Control and Prevention.
On Monday, the agency’s color-coded map showed California as having a “moderate” level of virus transmission, represented by yellow, with 48 other states stuck in the “high” transmission category, labeled red, and Connecticut advancing into the second-worst “substantial” tier, marked orange.
However, data published on Mondays can sometimes be off due to reporting irregularities over the weekend. Ali Bay, a spokesman for the California Department of Public Health, said that the state believes that the updated data would show that California is still technically in the orange category since data on cases are not reported on weekends.
Nonetheless, cases and hospitalizations have sharply declined in California as the state emerges on the other side of a sharp surge driven by the highly transmissible delta variant of the virus.
“California has the lowest COVID case rate in the country. The data doesn’t lie —vaccines work,” Gov. Gavin Newsom’s office tweeted on Monday.
Health experts have long credited California’s success to the state’s higher than average vaccination rates and thoughtful virus mitigation measures, including mask and vaccine mandates.
The state has yet to return to the “low” tier of COVID transmission, represented by blue on the map. It last achieved that in June.
The state’s virus positivity rate has dropped to 2.6% over the past eight weeks, the health department reports. About 59% of the population is vaccinated against COVID-19, slightly higher than the U.S. average of 57%.
The Bay Area is doing significantly better than California as a whole.
According to state data analyzed by The Chronicle, the Bay Area’s seven-day average daily case rate per 100,000 was nearly 40% better than California’s as a whole. Marin County has the lowest seven-day case rate in the state, followed by San Mateo County and Santa Clara County — with Alameda County, Sonoma County and San Francisco not far behind.
Note: This story has been updated with comments from the California Department of Health, which believes the state is still in the “substantial” transmission tier due to a weekend reporting lag.
Aidin Vaziri is a San Francisco Chronicle staff writer. Email: avaziri@sfchronicle.com