ABSTRACT
Background: National guidelines recommend that patients with high risk of allergic reactions to COVID-19 vaccinations must undergo allergological evaluation before authorizing vaccination. To date, allergological testing to COVID-19 vaccines and its excipients is not standardized. There is a need to provide more data on skin testing (ST) to COVID-19 vaccines. In this study, we aimed to evaluate the performance of skin testing with SARS-CoV- 2 vaccines and their excipients in our cohort of adult and pediatric patients. Method(s): All patients evaluated for a suspicion of allergy to any of the vaccine components (polyethylene glycols (PEGs) and polysorbate (PS)), or with a history of immediate or delayed reaction to a first injection of an mRNA vaccine were included. Evaluated patients received the following ST: *PEG 400 and 4000 (100 mg/ml), prick (PT) 1:1 and intradermal tests (IDR) 1:100,000, 1:10,000, 1:1000, 1:100, 1:10. *PS80 (0.4 mg/ml), PT 1:1, IDR 1:1000, 1:100, 1:10. *Tozinameran (Comirnaty) vaccine (30 mug/0.3 ml), PT 1:1 and IDR 1:10. ST readings were performed after 20 minutes for immediate reaction and 24 hours for delayed reaction. Patients were systematically contacted by phone after vaccination to assess side effects including anaphylaxis. Result(s): Between February 1st and October 31st 2021, 83 patients underwent allergological testing, with a majority of female (83.1%). Age (mean +/- SD) was 51 +/- 18 years old (yo) (range: 12-91 yo). Among those patients, 35 were tested following a reaction to the SARS-CoV- 2 vaccine and 48 for a suspected allergy to an excipient. No patients reported anaphylactic reaction after a COVID vaccine. Among them, 13 had positive ST (1 patient to PS80 IDR, 1 patient to PS80 PT and vaccine IDR, 11 patients to vaccine: 5 delayed IDR, 5 immediate IDR, 1 doubtful IDR). Eleven patients were vaccinated, well tolerated. We have no information about COVID vaccination for 2 patients. Out of the 70 patients with negative ST, 5 chose not to be vaccinated and 54 (77.1%) got vaccinated (11 (15.7%) did not respond to the phone call). No anaphylactic reactions were reported. Conclusion(s): In our cohort, vaccinations do not lead to hypersensitivity reactions, regardless of test results. We did not find real IgE mediated allergy. Vaccine IDR seemed too irritating and did not contribute to the diagnosis of vaccine hypersensitivity. The clinical context and skin tests results are helpful in authorizing vaccination.
ABSTRACT
Declaration de liens d'interets: Les auteurs declarent ne pas avoir de liens d'interets. Copyright © 2022
ABSTRACT
Background and importanceNational recommendations mention vaccinating against COVID-19 patients at risk of allergy after referring them to an allergologist. Included patients had suspected allergy to one of the vaccine’s components (polyethylene glycols (PEG) and polysorbates) or with a history of immediate reaction to a first injection of an mRNA vaccine. Patients at risk were referred to the allergology unit for investigation.Aim and objectivesThe purpose of this monocentric retrospective study was to assess positive skin tests (ST), and anaphylaxis reaction during vaccination after allergological work-up.Material and methodsFor any tested patient, pharmacy extemporaneously prepared: PEG 400 and 4000 (100 mg/mL), prick 1:1 and intradermal tests (IDT) 1:100 000, 1:10 000, 1:1000, 1:100, 1:10;polysorbate 80 (PS80) (0.4 mg/mL), prick 1:1, IDT 1:1000, 1:100, 1:10;and Comirnaty vaccine (30 µg/0.3 mL), prick 1:1 and IDT 1:10. ST readings were done after 20 minutes.Patients’ characteristics, test results and indications of allergological work-up were collected. Vaccination was authorised if negative ST. Patients were systematically recalled after vaccination to assess side effects including anaphylaxis.ResultsBetween 1 February and 31 August 2021, 49 patients, age (mean±SD) 54.5±17.8 years and female 81.6%, performed ST: 20 were tested after a reaction to the Comirnaty (19 after the first dose and 1 after the second dose) and 29 for a suspected allergy to an excipient. Among them, 3 had positive ST (one patient to PS80 prick test and vaccine IDT 1:10, and two patients to vaccine IDT 1:10 without positive ST to PS80 and PEG). Vaccination with Cominarty was contraindicated for these 3 patients. Four patients had delayed positive ST to the vaccine. They were not considered allergic and vaccination was authorised. Of the 46 patients with negative ST, 39 (85%) were vaccinated (one with VaxZveria) without any anaphylaxis reaction (7 did not answer the pharmacist’s call).Conclusion and relevancePositive ST to the vaccine are rare (6%). No patients had simultaneously positive ST to the vaccine and PEG. These results may suggest that the exact predictive positive value remain uncertain and that IDT to the vaccine might be irritating.References and/or acknowledgementsConflict of interestNo conflict of interest