Mark Ghaly, secretary of the state’s Health and Human Services department — a “significant reduction,” he said.

San Francisco’s vaccine supply — which goes to San Francisco General Hospital and city clinics that serve those who are insured or underinsured — could run dry by Thursday if the city doesn’t receive new shipments, Mayor London Breed said Tuesday.

Private providers have a separate vaccine pipeline, and Breed added that the city’s supply constraint “should not have a significant impact” on plans to open a mass vaccination center soon at City College.

San Francisco’s entire health care system — including both public and private providers — has received 102,825 doses of the vaccine as of Tuesday, Breed said.

Grant Colfax, San Francisco’s director of public health, said the city has received 8,000 doses from the Moderna lot that the state recommended not be administered pending further studies, following a spate of allergic reactions from the lot at Petco Park, the Padres’ stadium in San Diego.

Sara Cody, Santa Clara County’s public health officer, said the county received “a little over 21,000” of the Moderna doses under scrutiny, which had been scheduled to be distributed by the county, Stanford Health Care and El Camino Hospital.

Ghaly said a vaccine safety committee was meeting Tuesday to determine if the lot is safe, and “we believe we will come to some resolution soon.”.

San Francisco expects to receive another shipment of 1,775 doses this week, health officials said, but each of those have already been claimed — and that compares to 12,000 doses received last week.

Cody of Santa Clara County said the supply uncertainties made it “impossible for the county to plan ahead for vaccine distribution.” She added: “It's likely that future allocations will not distinguish between a first and second dose.”.