FDA Gives Guidance on Allergy, Pregnancy Concerns for Pfizer COVID Vaccine

Alicia Ault

December 12, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

The US Food and Drug Administration (FDA) has clarified its guidance on administration of the Pfizer/BioNTech COVID-19 vaccine, stating that it is safe for people with any history of allergies, but not for those who might have a known history of severe allergic reaction to any component of the vaccine.

The warning is included in the FDA's information sheet for health care providers, but questions are arising as to whether the vaccine — which was authorized for emergency use by the FDA on Friday — should not be given to anyone with a history of allergies.

Sara Oliver, MD, an epidemic intelligence service officer with the Centers for Disease Control and Prevention (CDC) reported at a December 11 meeting of the agency's Advisory Committee on Immunization Practices that two UK health care workers with a history of significant allergic reactions had a reaction to the Pfizer vaccine. A third health care worker with no history of allergies developed tachycardia, said Oliver.

"I want to reassure the public that although there were these few reactions in Great Britain, these were not seen in the larger clinical trial datasets," said Peter Marks, MD, PhD, director of the Center for Biologics Evaluation and Research (CBER) at the FDA, during a press briefing on December 12.

The Pfizer vaccine "is one that we're comfortable giving to patients who have had other allergic reactions besides those other than severe allergic reactions to a vaccine or one of its components," he said.

Marks suggested that individuals let their physicians know about any history of allergic reactions. He also noted that the federal government will be supplying vaccine administration sites, at least initially, with epinephrine, diphenhydramine, hydrocortisone, and other medications needed to manage allergic reactions.

The FDA is going to be monitoring side effects such as allergic reactions very closely, "but I think we still need to learn more and that's why we're going to be taking precautions. We may have to modify things as we move forward," said Marks.   

Oliver said that on December 12 the CDC convened an external panel with experience in vaccine safety, immunology, and allergies "to collate expert knowledge regarding possible cases," and that the FDA is getting more data from UK regulatory authorities.

Pregnancy Concerns

Agency officials had little to say, however, about the safety or efficacy of the vaccine for pregnant or breastfeeding women.

The FDA's information to health care professionals notes that "available data on Pfizer-BioNTech COVID-19 vaccine administered to pregnant women are insufficient to inform vaccine-associated risks in pregnancy."

Additionally, the agency stated, "data are not available to assess the effects of Pfizer-BioNTech COVID-19 vaccine on the breastfed infant or on milk production/excretion."

Marks said that for pregnant women and people who are immunocompromised, "it will be something that providers will need to consider on an individual basis." He suggested that individuals consult with physicians to weigh the potential benefits and potential risks.

"Certainly, COVID-19 in a pregnant woman is not a good thing," Marks said.

An individual might decide to go ahead with vaccination. "But that's not something we're recommending, that's something we're leaving up to the individual," he said.

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