The Food and Drug Administration (FDA) approved a booster dose of COVID-19 vaccines from Pfizer Inc (PFE.N) and Moderna Inc (MRNA.O) for people with compromised immune systems, according to The Washington Post.

The FDA's action means that additional shots could be available as soon as this weekend for patients who have had organ transplants or who have certain types of cancer or other illnesses.

Medical experts applauded the move, as they have lately become extremely worried about people who are unable to generate robust anti-virus responses even after being fully vaccinated. Details on how the shots will be administered, as well as who will be eligible for them, are expected to be worked out at a meeting of Centers for Disease Control and Prevention advisers on Friday.

Furthermore, the FDA decision updated the emergency use authorizations for the Pfizer-BioNTech and Moderna coronavirus vaccines, stating that an additional dose could be given to some immunocompromised people, specifically organ transplant recipients and others with similar levels of immune-system impairment.

On Friday, the CDC's Advisory Committee on Immunization Practices is expected to vote on recommending the additional doses and providing further details on how they will be administered.

Immunocompromised people are more likely to become seriously ill from covid-19, to spread the virus to household contacts, and to develop recurrent infections. According to experts, these people can also potentially spawn mutations that lead to dangerous new variants.