SACRAMENTO (CBS) — State health officials have announced that parents and legal guardians will be allowed to sign up their 12-to-15-year-old children for a dose of Pfizer COVID-19 vaccine starting Thursday morning.

The expanded eligibility announced late Wednesday night comes after the Centers for Disease Control and Prevention’s vaccine safety review panel and the Western States Scientific Safety Review Workgroup recommended that the vaccine is safe and effective in protecting 12-to-15-year-olds against severe illness, hospitalization and death.

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Signups for the shots can be made on the statewide booking system or by calling California’s COVID-19 Hotline at 1-833-422-4255.

“The more Californians who are able to get vaccinated, the better we can protect our communities and slow the spread of COVID-19,” said Gov. Gavin Newsom in a news release. “Our efforts to protect the health and wellbeing of Californians are paying off, as we’re now leading the country with over 32 million vaccines administered and some of the lowest positivity rates in the entire country. Having vaccines expanded to teenagers is the next step in California’s path to safely reopening next month.”

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The new order makes an additional 2.1 million Californians eligible for vaccination.

“California is ready to safely deliver vaccines to young people aged 12 and up,” said State Epidemiologist Dr. Erica Pan. “We have streamlined the enrollment process to include more clinics and providers that can administer vaccines to this next age group where they can also catch up on other vaccines that may have been missed over the course of this pandemic.”

The Pfizer vaccine is administered in two doses taken three weeks — 21 days — apart. It has already been safely administered to millions of California adults, including more than 30 percent of 16- and 17-year-olds.

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Pfizer was the first vaccine manufacturer to submit clinical trial data on the 12-15 age group to the FDA for authorization. Moderna is expected to submit trial data for the same authorization in the coming months. Johnson & Johnson is currently conducting clinical trials for the 12-17 age group.