WASHINGTON: US drug regulators say transplant recipients and others with severely weakened immune systems may receive an extra dose of Pfizer or Moderna vaccine to better protect them as the delta variant of the coronavirus continues to spread.

Late Thursday night, the announcement of the American Food and Drug Administration (FDA) refers to several million Americans who are especially vulnerable due to organ transplantation, cancer, or other disorders. Several other countries, including France and Israel, have similar recommendations, news agencies reported.

“This allows physicians to boost immunity in certain immunocompromised individuals who need additional protection from COVID-19,” Dr. Janet Woodcock, the FDA commissioner, said in a statement.

The FDA has determined that transplant recipients and others with similar levels of compromised immunity can receive a third dose of Pfizer and Moderna at least 28 days after receiving the second dose. The FDA did not mention immunocompromised patients who received the Johnson & Johnson single-dose vaccine.

The announcement comes as a result of an extremely contagious delta variant of the coronavirus that is spreading across much of the country, raising new cases, hospitalizations, and deaths to a height not seen since last winter.

Health authorities believe the extra dose is part of an initial prescription for people with weakened immune systems. For example, France has been encouraging such patients to receive a third dose since April, four weeks after a regular second injection.

Israel and Germany have also recently started recommending a third dose of the vaccine. (ANI/FENA)