A health care worker in Oregon was hospitalized this week after suffering a severe allergic reaction to Moderna's COVID-19 vaccine.
The worker is employed by Wallowa Memorial Hospital. The worker, who was not identified, is recovering at a hospital after experiencing the reaction, or anaphylaxis, the Oregon Health Authority said in a statement.
The hospital shared the authority's statement but gave no further information.
According to the Food and Drug Administration, there is "a remote chance" that Moderna's vaccine could cause a severe allergic reaction. The reaction would usually occur within a few minutes to one hour after getting injected, drug regulators said in a fact sheet.
Signs of a severe allergic reaction can include difficulty breathing, a fast heartbeat, and dizziness.
"Those who have had an immediate allergic reaction—even if it was not severe—to a vaccine or injectable therapy for any disease should ask their health care provider if they should get a COVID-19 vaccine. Your provider will help you decide if it is safe for you to get vaccinated," the authority said in a statement.
While the vaccines are approved under emergency use authorization, they were the fastest-approved vaccines in history.
A federal panel said last month that surveillance of both vaccines "will be critical to detect any rare serious adverse events which were not identified" in the phase 3 clinical trial.
"As with any medicine that is being distributed to millions of people, we expect to see some side effects. Rare, but serious side effects can happen. There have been several people who after the vaccine have had severe allergic reactions. CDC takes these reports very seriously and has been meeting regularly with the FDA, our partner in monitoring vaccine safety, to discuss," Dr. Nancy Messonnier, director of the CDC's National Center for Immunization and Respiratory Diseases, told reporters during a call on Wednesday.
Approximately 2.8 million Americans have been vaccinated as of Thursday morning, according to the CDC.
Some adverse reactions are detailed in the agency's Vaccine Adverse Event Reporting System. One example took place in Alaska on Dec. 17 with Pfizer's vaccine.
The person getting the vaccine was a 40-year-old woman with a history of severe allergic reaction to a flu vaccine. She chose to proceed despite being told vaccination could be deferred until more information about the vaccine becomes known. She developed "throat tightening" approximately 20 minutes after vaccination, according to the medical report. She received an EpiPen and was sent to the emergency room.
"It’s widely recommended for everyone because we know it’s 95 percent effective, as much as 100 percent effective at preventing severe disease," Adm. Brett Giroir, assistant secretary for health and part of the White House Coronavirus Task Force, said during a recent TV appearance. "And this is the way we end the pandemic, by getting 70 percent or 80 percent of the American people vaccinated."