HARRISBURG, Pa. (WHTM) — The Centers for Disease Control and Prevention have signed off on a third COVID vaccine dose for some Americans.

Doctors say first and foremost, these doses are not for everyone they’re specifically for “immunocompromised” people.

Experts share exactly what this means.

Americans at high risk for the coronavirus because they have compromised immune systems can seek a third shot of either the Pfizer or Moderna vaccine.

“Basically what we are looking at is how many breakthrough infections are we seeing in the general public now,” Penn State Health Infectious Disease Dr. Mohammad Ali said.

Dr. Ali says for now this is only for a narrow group such as people who’ve had heart complications, certain cancers, HIV, and patients who are on multiple medicines that affect their immune system.

“For the general public it’s going to take some time, I don’t think we’re at that stage everybody would get a booster or people broaden the category for example to older people or people with underlying conditions not associated to their immune systems but other conditions,” Dr. Ali said.

Dr. Ali also says if you think you might be in an immunocompromised group but aren’t sure or may not be comfortable with the idea of a booster shot you should talk to your doctor.

“If you feel that you should get a booster shot you need to get in touch with your primary care physician an at least or if there’s another physician treating you for a specific condition that weakens the immune system you need to get in touch and ask them if you fall in that category before you go out and get one,” Dr. Ali said.