SAN FRANCISCO, Calif. (KRON) – Over the past week, there have been more than 69,000 COVID infections in California.

In the last 24 hours, health officials reported 9,500 cases, 8,500 on Tuesday, 7,300 Wednesday, more than 33,000 over the weekend, and 10,000 last Thursday.

That breaks down to nearly 10,000 new cases per day.

A new sub-strain of the delta variant has been detected here in the Bay Area. It’s called delta plus and officials say it’s the most contagious variant we’ve seen.

“So what you see is like bad stuff just getting worse because they’re mutating,” Dr. Peter Chin-Hong, UCSF infectious disease specialist, said. 

The delta variant is the most contagious coronavirus mutant so far in the pandemic and now there’s a variation of that variant and it’s gaining speed.

The delta plus was first detected in Europe back in March. Doctors say it’s more transmissible than the original delta variant and that it latches onto lung cells more easily.

“While this delta plus has been identified and has changes that suggest the possibility of it being a problem for us it hasn’t exploded,” Dr. John Swartzberg, clinical professor at the Emeritus School of Public Health Division of Infectious Diseases, said. 

The county of Santa Clara is already tracking it on their website though. They say it exists statewide and nationwide and that there is not enough information right now to indicate if it should be more concerning than the original delta variant.

As of last week, 298 people in Santa Clara County had the delta variant and 47 tested positive for its substrain, the delta plus.

Alameda County reports fewer than 10 cases as of last Tuesday and Contra Costa County health officials say less than 7-percent of their detected delta cases have been delta plus.

“COVID is just throwing all our rules out the window and the reason why is there’s so much transmission all around the world that you are just getting more and more chances for mischief to occur from the perspective of the virus,” Dr. Chin-Hong said. 

The CDC is recommending fully vaccinated people to return to wearing masks indoors because of the delta surge and 8 Bay Area counties are requiring this because of the delta’s high transmission, vaccinated people can get infected and this variant spreads more easily.

“We are still protected from serious disease that’s hospitalizations, deaths and being on a ventilator for example but again things may change over time as continued transmission will create variants that may be more vaccine evasive than what we know about so far,” Dr. Chin-Hong said.