(NEXSTAR) – When the vaccines against COVID-19 first came out, health officials advised everyone get “fully vaccinated” as soon as they were eligible. At the time, that meant two doses of the Moderna or Pfizer vaccine, or one dose of the Johnson & Johnson vaccine. It’s safe to say that things have changed since then.

Since then, the Food and Drug Administration has approved the use of multiple rounds of booster shots depending on your age, health of your immune system and how long it has been since your last shot. A new type of vaccine, a bivalent formula that targets the original and omicron strains of the virus, has also been released.

However, that has not changed the definition of “fully vaccinated,” according to the CDC.

“You are fully vaccinated even if you haven’t gotten your booster yet. The definition of fully vaccinated does not include a COVID-19 booster,” the CDC guidance reads. “Fully vaccinated, however, is not the same as having the best protection.”

That’s why the CDC, as well as other health authorities, have moved away from emphasizing the importance of being “fully vaccinated” and have moved toward encouraging staying “up to date” with vaccine doses.

Being “up to date” means you’ve gotten the most recent dose you’re eligible for.

For an average adult who’s had at least two doses of a COVID-19 vaccine (meaning you’ve completed your “primary series”), and it’s been more than two months since your last dose, you need to get the bivalent booster to be considered up to date.

Young children and immunocompromised people have different recommendations to follow.

The CDC has created a tool to help you determine if it’s time to get another dose.