SAN FRANCISCO (CBS SF/AP) — California has surpassed 4 million COVID-19 vaccinations administered, but a shortage of the two approved coronavirus vaccines is forcing local officials across the state including in Napa County to restrict who gets shots.

Gov. Gavin Newsom took to Twitter Saturday morning to spread the word of the 4-million milestone.

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“CA has administered over 4 million #COVID19 vaccines,” he posted. “We’re now administering about a million doses a week. Hope is on the horizon.”

Some 4.2 million shots have been administered statewide, but health officials could not immediately say how many of those were second shots that would reflect the number of people in the state’s population of nearly 40 million with maximum protection from the virus.

While the milestone was greeted with much optimism, supplies of the two approved vaccines were running low in many counties.

Napa County has stopped giving first doses to preserve its remaining supply for those who are ready for second shots. Pfizer and Moderna each say two shots are required for their vaccines to be most effective.

Napa County Supervisor Alfredo Pedroza said officials are now having to “manage the expectations” of the 27,000 people who took the first dose and another 46,000 who have made appointments and are waiting to get the first shot.

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“We’re getting a lot of the questions from community members asking, ‘is my second dose in jeopardy?’ And right now, we don’t have an answer,” Pedroza said. “There’s a lot of frustration, there’s a lot of emotion because there’s been a lot of mixed messages.”

Newsom has acknowledged the initial vaccine rollout was unacceptably slow and had the state ranked near the bottom nationally. There’s been improvement and the state now is averaging 1 million shots a week but limits on the supply coming from the federal government means California’s capacity to provide shots far outstrips available vaccine.

Santa Clara County, which has about 2 million residents, plans to use a mass vaccination site opening at Levi’s Stadium to significantly increase its numbers. It will start out by administering 5,000 shots a day and as supplies increase will be able to triple that.

Kaiser Permanente has opened two mass vaccination centers under an agreement with the state, one at Moscone Center and the other at Cal Poly Pomona, in Los Angeles County, each with the capacity to administer up to 10,000 doses a day.

Meanwhile, the state’s worst coronavirus surge continues to abate as new virus cases fall sharply. The daily average now is about 14,500 cases, down almost 50% from two weeks ago.

The California Department of Public Health rescinded its hospital surge order, which had required hospitals to delay some elective surgeries and to accept patients from other counties whose intensive care unit capacity had dropped below 15%.

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Deaths also are starting to fall but remain exceptionally high. Another 558 were announced Friday and in the last week almost 3,500 have died.