You probably qualify for a COVID-19 booster already, even if you don't realize it, several health experts say

• The CDC recommends COVID-19 boosters for certain adults who got vaccinated at least six months ago.
• But several health experts told Insider that most Americans likely meet at least one of the CDC's criteria.

The Centers for Disease Control and Prevention expanded its COVID-19 booster recommendations to a wider group of people last week, but stopped short of suggesting boosters for all adults in the US.

People who were vaccinated with Pfizer's or Moderna's shot at least six months ago should seek a booster if they're 65 and older, live or work in settings with high levels of exposure to the virus, or have underlying medical conditions, according to the CDC. The agency also recommends boosters for any adult who received Johnson & Johnson's vaccine at least two months ago.

Health experts say that list isn't as restrictive as it sounds.

"If you think about it, and you read what the CDC says, there's a lot of people basically that should get boosters," Bernadette Boden-Albala, director of the University of California, Irvine's public-health program, told Insider. She added, "the majority of people are going to meet one of the criteria."

Other experts agree that there's room for interpretation within the CDC guidelines, so people who aren't sure whether they qualify for boosters should check with their doctor. More than 108 million people in the US - roughly one-third of the US population - were fully vaccinated at least six months ago, according to the CDC. And nearly 15 million people have received a J&J shot.

"The guidelines are unnecessarily complex, but there is a fair degree of latitude," David O'Connor, a pathology professor at the University of Wisconsin, told Insider.

Here's how experts are interpreting the CDC's recommendations.

The CDC doesn't list every health problem that may qualify people for boosters

The CDC website gives examples of underlying health problems that may qualify someone for a booster: diabetes, pregnancy, obesity, depression, and a history of smoking, among others. But the CDC also notes that the list "does not include all possible conditions that place you at higher risk of severe illness from COVID-19."

"People need to really look and read through the eligibility for boosters and then, if they're still confused about whether they should get a booster or not, they should talk to their healthcare professional because a lot of people are going to be covered," Boden-Albala said.

Nearly half of US adults, for instance, have hypertension (high blood pressure) - a condition that could increase your risk of severe COVID-19, according to the CDC.

Still, some experts are wary of people intrepreting the guidelines too freely.

"If you're healthy, I think you can probably hold off now," Dr. Simon Li, who helps run the Pfizer COVID-19 pediatric vaccine clinical trial at Rutgers University, told Insider. "But if you're not healthy, or do have a preexisting condition or you have hypertension or any other diseases that can affect your immune system, then you should consider it."

Many Americans face exposure to COVID-19 at work

The CDC currently recommends boosters for first responders, education staff, postal service workers, grocery store employees, and people who work in manufacturing, food and agriculture, corrections, or public transit.

O'Connor said those are merely examples, since there's no hard and fast definition of a high-risk work environment.

"If you're going to be exposed to the virus, then you're potentially in a high-risk environment," he said. "There's enough latitude right now that you can self-select yourself into one of those groups, if you are so inclined."

There's a reason the CDC hasn't recommended boosters for all, though: Data still show that COVID-19 vaccines are highly protective against hospitalization and death at least six months out among people who aren't older or immunocompromised.

Some experts have even questioned whether the existing CDC guidelines are too broad.

"I don't think that we have evidence that everybody in those groups needs a booster today," Dr. Matthew Daley, a member of the of the CDC's Advisory Committee on Immunization Practices, recently told The New York Times.

But O'Connor said all adults should have the option to seek out boosters, even if it's just to protect themselves from mild disease.

"Let people make their own decisions based on the merits," he said. "There really aren't very many good reasons not to."

Erin Schumaker contributed reporting.