SANTA ROSA (CBS SF) — More than 9,000 youth ages 5-to-11 living in Sonoma County have received their first dose of the Pfizer-BioNTech vaccine since it became available a month ago, according to health officials.

That represents 25 percent of the Sonoma County residents in that age group. Health officials said that 75 percent of eligible county residents who are age 5 and older are now fully vaccinated against COVID-19, while another 38,428 residents, or 8 percent of the county’s eligible population of 470,488 residents, have been partially vaccinated.

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The pediatric vaccine campaign began Oct. 20, featuring clinics at multiple school sites. The county aims to vaccinate half of eligible children by Jan. 31 and 70 percent by Feb. 28.

Dr. Sundari Mase, Sonoma County’s health officer, congratulated parents for getting their children vaccinated and emphasized the importance of vaccines as winter could lead to a rise in COVID-19 cases.

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“We are thrilled that so many of our younger children have received their first dose,” Mase said. “We are off to a good start, but we need to maintain our momentum. Everyone who has waited to get vaccinated should get their first dose as soon as possible. This is a winter virus, and it is still circulating in the community. Getting vaccinated will help contain the virus and save lives.”

While severe illness due to COVID-19 is rare among children, they can become very sick. Almost 7 million children have tested positive for COVID-19 since the onset of the pandemic, according to the U.S. Centers for Disease Control and Prevention.

Residents were also encouraged to get a booster shot now that all adults 18 and older are eligible. Anyone 18 or older can choose either a Pfizer or Moderna booster six months after their last dose. For anyone who got the single-dose Johnson & Johnson vaccine, the wait is just two months. And people can mix-and-match boosters from any company.

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Walk-ups are accepted at most clinics and pharmacies. Residents also may make appointments at the county’s vaccine clinic page or through the myturn.ca.gov web site. Residents who need help making an appointment are encouraged to call the county COVID-19 hotline at (707) 565-4667.