The New York Times reported Wednesday that a health worker living in Alaska developed a serious allergic reaction after she received an injection of the new Pfizer/BioNTech virus vaccine, which necessitated her hospitalization.

This nurse, whose name has not been revealed, had no previous known allergies and is now in stable condition, according to the newspaper.

Pfizer confirmed that it is working on coordination with local health authorities on the case.

A spokesman for Pfizer confirmed, "We will closely study all information about a serious allergy and will update if necessary the leaflet for the vaccine.

British health authorities recommended Dec. 9 that the Pfizer/BioNTech vaccine not be given to people who had suffered in the past from "severe allergies," after two people showed a bad reaction after receiving the first dose.

Friday evening, the United States gave its green light to start using the Pfizer/BioNTech vaccine, which opened the way for a nationwide mass vaccination campaign that began Monday.

The United States plans to vaccinate three million people this week and hopes to vaccinate up to 20 million people if the US Food and Drug Administration also gives an urgent license to Moderna vaccine by the end of the week.