SAN JOSE (CBS SF) – Health officials in Santa Clara County on Wednesday urged all adults in the county to receive a booster dose of the COVID-19 vaccine amid concerns about a potential rise in cases over the holidays.

The Santa Clara County Public Health Department made the recommendation amid concerns of immunity waning over time along with an expected rise in holiday gatherings.

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Relatively few residents have received booster shots. Officials said as of Tuesday, only 206,765 residents out of more than 1.08 million have received the third dose, less than 20%.

“I think what the public heard was, ‘I have to be 65 otherwise I shouldn’t get a booster.’ And that’s not correct. That’s not correct,” Santa Clara County Health Officer Dr. Sara Cody said at a briefing Wednesday.

Cody said the Centers for Disease Control guidelines for booster shots — anyone 65 and older, people with underlying medical conditions or a risk of exposure — apply to basically everyone.

“The holidays are coming. Our case rates are flat to increasing. People are going to be gathering. And there’s a tool available, widely available that we can all use to increase our safety and protection. And that’s a booster shot,” Cody said.

The mixed messages about booster eligibility from the CDC, Dr. Cody warns, have led to a sluggish rollout of the third shot. She said she fear that without a booster people may be vulnerable to the virus and not even realize it.

“I want to make sure that I’m protected and protecting my community. And I am planning to travel a little bit,” says Ornit Baz, who received her booster Wednesday. Baz told KPIX 5 that didn’t need much convincing to get a booster because she had heard about waning vaccine effectiveness from family members in Israel.

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Santa Clara is so far the only Bay Area County urging everyone who’s been fully vaccinated to get a booster. But Cody said it’s the safest way to travel or visit with family for Thanksgiving.

“We know that protection fades from the original vaccine series. So, it is important to get a booster,” she said.

Dr. Marty Fenstersheib, the county’s COVID-19 vaccine officer said plenty of doses are available.

“This is a safe and easy way to make the holidays safer for our loved ones,” Fenstersheib said.

Health officials said booster doses for the Pfizer, Moderna and the Johnson & Johnson shots are readily available and are being offered at no cost to the public.

Information about vaccine appointments at county clinics can be found at sccfreevax.org. COVID-19 vaccines are also available at many doctor’s offices and pharmacies.

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Devin Fehely contributed to this report.