SACRAMENTO (CBS SF) – California health officials on Wednesday expanded the proof of vaccination requirement to attend large indoor gatherings such as concerts and sporting events, amid the ongoing surge in cases due to the Delta variant.

The California Department of Public Health announced that as of September 20, proof of vaccination or a negative COVID-19 test taken within 72 hours will be required to enter indoor events of 1,000 people or more. Currently, the vaccination and testing requirement is necessary for events with at least 5,000 people indoors.

CDPH also announced that self-attestation to verify one’s vaccination status will no longer be accepted.

“The Delta variant has proven to be highly transmissible, making it easier to spread in large crowds where people are near each other for long periods of time,” state health officer Dr. Tomas Aragon said. “By requiring individuals to be vaccinated, or test negative for COVID-19 at large events, we are decreasing the risk of infection, hospitalization and death.”

The tougher rules come as COVID-19 cases driven by the Delta variant continue to surge in the state, largely among the unvaccinated. Health officials said for the week of August 9-15, the average case rate among unvaccinated Californians is 51 per 100,000 per day, compared to 7.6 among residents who have received the vaccine.

Large concert and event promoters, including Live Nation Entertainment and AEG, backed the new vaccination and testing requirement.

“We fully support California’s efforts and will stay in lockstep to keep bringing live music back to the Golden State,” Michael Rapino, president and CEO of Live Nation, said in the CDPH statement.

AEG president and CEO Dan Beckerman said, “Today’s announcement adds another layer of protection to make our State, our venues and our communities safer. Our fans, our team members and our families all want to feel as protected as possible from COVID-19 while enjoying our favorite concerts and sporting events.”

CDPH said the new rules regarding indoor events will remain in effect through at least November 1.

Information about vaccination appointments can be found at http://myturn.ca.gov or by calling 833-422-4255. People seeking vaccination can find information about walk-in clinics by visiting http://myturn.ca.gov/clinic.