REDWOOD CITY (CBS SF/BCN) — A steady decline in new cases and progress in delivering vaccinations has San Mateo County health officials optimistic even if the supply of COVID-19 vaccine is currently less than promised.

As of Monday, 49.5 percent of San Mateo County residents 16 and older have received at least the first dose of the COVID-19 vaccine.

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Dr. Anand Chabra, San Mateo County Health COVID-19 mass vaccination section chief, says that the county received 17,420 vaccine doses last week, fewer than the 20,930 doses received two weeks ago.

Chabra said the change may be because some vaccine outlets — like Stanford Health Care and Safeway pharmacy — received doses directly from the California Department of Public Health as part of the state’s arrangement with Blue Shield of California, the third-party vaccine administrator.

“We’ll see additional providers receive direct allocations from the state through the Blue Shield arrangement in the coming weeks,” Chabra said. “We still do not have sufficient supply to meet demand. But the state is now providing some projections of supply for coming weeks. That does help with planning.”

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Chief of San Mateo County Health Louise Rogers said the state expects to increase the vaccine supply in a couple of weeks.

“Unfortunately, we don’t have any really specific information for San Mateo County,” Rogers said. “We remain hopeful because the eligibility groups are expanding quite dramatically on April 15.”

That is the date when all California residents 16 and older will become eligible for the vaccine. On April 1, individuals 50 and older became eligible for the vaccine, joining essential workers, the elderly population and other high-risk groups.

Vaccination opportunities are available through health care providers, community clinics or pharmacies.

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For more information on COVID-19 vaccinations in San Mateo County and to sign up for the county’s notification tool, people can visit www.smchealth.org/covidvaccine.