San Francisco is nearing herd immunity, some experts believe, a milestone in California’s efforts to gain control of the COVID-19 pandemic. People without immunity to a disease are indirectly protected by herd immunity. “I think San Francisco is pretty close,” said UC San Francisco epidemiologist Dr. George Rutherford, who believes north of 75% of a population likely needs to be immune before herd immunity is achieved. AdvertisementNothing suddenly happens when herd immunity is achieved — daily coronavirus case rates are already extraordinarily low in San Francisco. And, technically, herd immunity is achieved gradually: The more people who gain immunity, the slower the rate of disease transmission.

Source: Los Angeles Times June 09, 2021 15:00 UTC