Some of the celebration and excitement over the approval of the COVID vaccines has been dampened by recent reports of allergic complications. Twenty-one cases of confirmed anaphylaxis were identified after the first 1.8 million doses of the Pfizer-BioNTech vaccine were administered (roughly 1 in 87,000 injections). Though rare, this is substantially higher than the risk associated with other vaccines (1.3 per million).
So far, the majority of episodes of anaphylaxis occurred within 30 minutes of receiving the vaccine and readily responded to treatment. Of 21 identified case reports, five patients were food allergic, of whom three also had a history of drug allergy. A total of 12 patients had had prior allergic reactions to medications or vaccines, and one patient had environmental allergies.
As for the Moderna vaccine, a couple of cases of delayed facial swelling have occurred without serious consequences. The Centers for Disease Control and Prevention (CDC) now recommends a brief period of observation after vaccination in a facility that is capable of and prepared to treat anaphylaxis.
So, what's the most likely cause of these reactions, and how can we keep our patients safe? Here are the answers to some questions you might have.
