Assessment of Immediate Allergic Reactions After Immunization With the Pfizer BNT162b2 Vaccine Using Intradermal Skin Testing With the COVID-19 Vaccines.

BACKGROUND: Allergic reactions to the coronavirus disease 2019 (COVID-19) vaccines have raised concerns, particularly as repeated doses are required. Skin tests with the vaccines excipient were found to be of low value, whereas the utility of skin tests with the whole vaccine is yet to be determined. OBJECTIVE: To evaluate a panel of skin tests and the outcomes of subsequent doses of immunization among subjects who suffered an immediate allergic reaction to the BioNTech (BNT162b2) COVID-19 vaccine. METHODS: Between March and December 2021, patients who experienced symptoms consistent with immediate allergic reactions to the BNT162b2 vaccine and were referred to the Sheba Medical Center underwent skin testing with polyethylene glyol (PEG)-containing medicines, Pfizer-BNT162b2, and Oxford-AstraZeneca vaccine (AZD1222). Further immunization was performed accordingly and under medical observation. RESULTS: A total of 51 patients underwent skin testing for suspected allergy to the COVID vaccines, of which 38 of 51 (74.5%) were nonreactive, 7 of 51(13.7%) had no skin sensitization but suffered a clinical reaction during skin testing (mainly cough), and 6 of 51 (11.7%) exhibited immediate skin sensitization. Both skin sensitization and cough during testing were related to a higher use of adrenaline following immunization (P = .08 and P = .024, respectively). Further immunization with the BNT162b2 vaccine was recommended unless sensitization or severe reaction to previous immunization was evident. The latter were referred to be tested/receive the alternative AZD1222 vaccine. Ten patients underwent skin testing with AZD1222: 2 of 10 (20%) demonstrated skin sensitization to both vaccines; thus, 8 of 10 were immunized with the AZD1222, of which 2 of 8 (25%) had allergic reactions. CONCLUSIONS: Immediate allergic reactions to COVID-19 vaccines are rare but can be severe and reoccur. Intradermal testing with the whole vaccine may discriminate sensitized subjects, detect cross-sensitization between vaccines, and enable estimation of patients at higher risk.

Prevalence of Allergic Reactions After Pfizer-BioNTech COVID-19 Vaccination Among Adults With High Allergy Risk.

Importance: Allergic reactions among some individuals who received the Pfizer-BioNTech (BNT162b2) COVID-19 vaccine discourage patients with allergic conditions from receiving this vaccine and physicians from recommending the vaccine. Objective: To describe the assessment and immunization of highly allergic individuals with the BNT162b2 vaccine. Design, Setting, and Participants: In a prospective cohort study from December 27, 2020, to February 22, 2021, 8102 patients with allergies who applied to the COVID 19 vaccine referral center at the Sheba Medical Center underwent risk assessment using an algorithm that included a detailed questionnaire. High-risk patients (n = 429) were considered "highly allergic" and were immunized under medical supervision. Exposures: Pfizer-BioNTech (BNT162b2) COVID-19 vaccine. Main Outcomes and Measures: Allergic and anaphylactic reactions after the first and second doses of BNT162b2 vaccine among highly allergic patients. Results: Of the 429 individuals who applied to the COVID-19 referral center and were defined as highly allergic, 304 (70.9%) were women and the mean (SD) age was 52 (16) years. This highly allergic group was referred to receive immunization under medical supervision. After the first dose of the BNT162b2 vaccine, 420 patients (97.9%) had no immediate allergic event, 6 (1.4%) developed minor allergic responses, and 3 (0.7%) had anaphylactic reactions. During the study period, 218 highly allergic patients (50.8%) received the second BNT162b2 vaccine dose, of which 214 (98.2%) had no allergic reactions and 4 patients (1.8%) had minor allergic reactions. Other immediate and late reactions were comparable with those seen in the general population, except for delayed itch and skin eruption, which were more common among allergic patients. Conclusions and Relevance: The rate of allergic reactions to BNT162b2 vaccine, is higher among patients with allergies, particularly among a subgroup with a history of high-risk allergies. This study suggests that most patients with a history of allergic diseases and, particularly, highly allergic patients can be safely immunized by using an algorithm that can be implemented in different medical facilities and includes a referral center, a risk assessment questionnaire, and a setting for immunization under medical supervision of highly allergic patients. Further studies are required to define more specific risk factors for allergic reactions to the BNT162b2 vaccine.