SAN FRANCISCO (CBS SF) — San Francisco could be the next Bay Area city to issue an indoor mask mandate amid a COVID case surge that has included over 200 vaccinated health care professionals at hospitals.

San Francisco health officials say the city is averaging 176 new cases a day in the past week, a ten-fold jump from the beginning of June. Most cases have been in unvaccinated or partially-vaccinated people, but there has been a notable amount of cases among the vaccinated as well.

READ MORE: Emeryville Tax Preparer Accused Of Filing Dozens Of Fraudulent Returns, Teaching Fraud In 'Tax School'

On Friday, KPIX learned hundreds of fully vaccinated hospital workers in SF have tested positive for COVID-19, though San Francisco Public Health Director Grant Colfax said at a press conference earlier that most were not infected at the workplace.

“The Delta variant is a different beast, and it still be there when vaccinated,” said Dr. Monica Gandhi, a UCSF professor and infectious disease expert. “We are seeing health care workers who are being diagnosed with COVID-19, but thankfully most of these health care workers are fully vaccinated.”

At San Francisco General Hospital, 35 staff members were out sick after testing positive for the coronavirus. According to the hospital’s chief medical officer and the San Francisco Chronicle, three-quarters of them were fully vaccinated.

Dr. Lukejohn Day of S.F. General said all of these cases were contracted outside the hospital since strict PPE protocols are still in place inside.

“Our PPE requirements have not changed since the beginning of the pandemic. We have always adhered to them so strictly we have not had any patient-to-staff or staff-to-patient transmissions,” Dr. Day told KPIX.

He expected that, through the pandemic, 10 to 20 percent of his staff would be sickened by COVID-19 but, between safety protocols and vaccines, that has not happened.

“We didn’t see that for the first couple of surges and I think that was really due to the sheltering in place that was in effect through San Francisco and the Bay Area,” Dr. Day said.

READ MORE: Liana Wallace On 'Survivor' All-Black Alliance Falling Apart: 'Just Wanted Us To Make Top 8, Then We Can Have World War II''

UCSF released a statement regarding COVID infections among staff members across both the health system and the university campus early Friday evening. The statement said 92% of the hospital’s frontline health workers have been vaccinated and more than 90% across the UCSF health, campus employee and trainee population have been vaccinated overall.

In the past month, UCSF has had 183 employees or learners test positive for COVID-19 out of a total UCSF population of approximately 35,000. The statement said 90% of those were cases acquired in the person’s community or home.

Of those, 153 had been vaccinated and 30 had not. Officials said only two of the vaccinated cases required hospitalization. Without vaccinations, hospital officials said they would expect to have 767 COVID-19 cases given the current positivity rate among those UCSF individuals who have not been vaccinated.

With the number of cases rise again due to the Delta variant, UCSF officials said they were doubling down on efforts to protect staff. That includes requiring all employees and trainees comply with the new UC-systemwide COVID-19 vaccination mandate, though there are limited exceptions for medical or religious reasons.

UCSF has also have reinstated masking requirement at all levels across the university, including staff, patients and visitors, as well as quarantines for those who have been exposed to COVID-19 in their households, to prevent transmission to others.

Doctors say for now, the best methods of protection are getting vaccinated and wearing a mask indoors.

“We Are very vigorously exploring a mask mandate and in discussions with surrounding counties and health officers.”

A new mask mandate could be coming in the near future, though it will ultimately be decided on a county by county basis as the new delta variant becomes more widespread.

MORE NEWS: Man Wins $1 Million On Scratch-Off Lottery Ticket Gifted To Him After Heart Surgery

KPIX 5’s Andria Borba and Juliette Goodrich contributed to this report