All fully vaccinated adults in California seeking a COVID-19 booster shot should be eligible to get one, California Department of Public Health officials say.

In a letter Thursday, officials directed health care providers not to deny booster shots to adult patients. The announcement opened up booster shot eligibility to millions of residents across the state.

"Do not turn a patient away who is requesting a booster," California Department of Public Health Director Tomás J. Aragón said in the letter. "Allow patients to self-determine their risk of exposure."

People in California who are 18 and older are eligible for a COVID booster shot as long as at least six months have passed their second dose of the two-shot Pfizer or Moderna vaccine or two months must have passed since their Johnson & Johnson shot.

The Centers for Disease Control and Prevention recommends that any adult who is 65 or older who has received any of the three vaccines should get a booster shot. It only recommends boosters for people who are 18 and older if they live or work in long-term or high-risk settings or have an underlying health condition.

"These recommendations are another example of our fundamental commitment to protect as many people as possible from COVID-19," CDC Director Rochelle P. Walensky said in a statement regarding booster shot eligibility.

According to the agency, less than 40% of fully vaccinated adults 65 and older in California have received a booster shot. And among all fully vaccinated adults 18 and older in the state, nearly 14% have received a booster shot.

"If you think you will benefit from getting a booster shot, I encourage you to go out and get it," said Dr. Mark Ghaly, secretary of the California Health and Human Services Agency in a news conference Wednesday.

Colorado also has expanded eligibility. Gov. Jared Polis signed an executive order Thursday allowing all adults in the state to get a COVID-19 booster shot.

"The health and safety of Coloradans has been my top priority throughout this global pandemic. We want to ensure that Coloradans have every tool they need to protect themselves from this deadly virus and to help reduce the stress on our hospitals and health care workers," Polis said in a statement.

Earlier this week, Colorado officials issued a public health order preventing any vaccine provider from refusing a COVID-19 vaccine booster shot to anyone who meets the qualifications.

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