Connecticut has begun administering the third dose of the Pfizer and Moderna vaccines to those who are immunocompromised.

Gov. Ned Lamont says currently, only people with compromised immune systems can get a third dose of the vaccine. The shot is available at hundreds of CVS and Walgreens locations across the state.

The state Department of Public Health says those who are moderately or severely immunocompromised can get a third dose of either the Pfizer or Moderna vaccines at least four weeks following their second dose.

Recipients who qualify include those who have received a solid organ transplant, those with moderate or severe primary immunodeficiencies like DiGeorge syndrome, those with advanced or untreated HIV, cancer patients undergoing chemotherapy, and a few other groups.

MORE: Moderately to severely immunocompromised people who qualify for 3rd shot

The FDA amended its emergency use of the Pfizer and Moderna vaccines allowing certain people with compromised immune systems to get a third dose. The amendment does not apply to the Johnson & Johnson vaccine.

The third dose is also being offered at walk-in clinics where no appointment is needed.