State public health officials on Friday began sending text notifications to Coloradans who the state says are due for a COVID-19 vaccine booster dose.

The Colorado Department of Public Health and Environment announced Friday that the text notifications will go out over the next 13 days to people whose records in the Colorado Immunization Information System indicate they are:

• 18 or older and at least six months past their Pfizer or Moderna series
• 18 or older and at least two months past their Johnson & Johnson shot

The text messages, from the number 45778, will go out to more than 1 million Coloradans, the state health department said in a statement.

On Thursday, the CDC announced that it recommends a COVID-19 booster shot for “certain populations,” a more narrow spectrum than Colorado’s text advisory, which tells recipients over 18 they “are due for a booster.”

The CDC’s authorization states that the following groups of people who’ve received a Pfizer or Moderna COVID-19 vaccine, and are 6 months or more out from their second shot, should receive a booster:

• 65 years and older
• 18 or older who live in long-term care settings
• 18 or older who have certain underlying medical conditions
• 18 or older who work or live in high-risk settings

For the nearly 15 million people who got the one-dose Johnson & Johnson COVID-19 vaccine nationwide, booster shots are recommended for those who are 18 and older and who were vaccinated two or more months ago.

Colorado health officials said the “green light for a booster across a wide swath of the population” is based, in part, on the CDC’s Thursday recommendations.

“The state has no way of knowing if people work in high-risk settings or have underlying medical history, so we are alerting everyone within the eligibility timeline,” a spokeswoman for the state health department said in an email. “The state has ample inventory to offer booster doses to those who are eligible while continuing to provide first and second doses to people completing their initial vaccine series.”

The text for Pfizer and Moderna recipients states: “State public health records show you completed your primary COVID vaccine series at least 6 months ago and if so are due for a booster.” The message then directs the recipient to a state website listing vaccination sites.

Also on Friday, Gov. Jared Polis urged Coloradans to get vaccinated and for already vaccinated residents to go for a booster.

“The safe and effective vaccine and now the booster is the ticket to safety and the best way to avoid overwhelming our health care system,” Polis said in a news release. “This is an extremely dangerous time for unvaccinated individuals, so go get vaccinated today or get your booster — it could save your life and the lives of those you love.”

Polis said he “eagerly rolled up his sleeve” to receive a booster shot on Friday.