SARS-CoV-2 and allergy - what have we learned after two and a half years?

BACKGROUND

Coronavirus disease-2019 (COVID-19) has significantly hampered the regular workflow for allergists and allergy departments.

MATERIALS AND METHODS

The purpose of this review is to highlight our own experiences on SARS-CoV-2 and allergy as well as to discuss findings from the literature.

RESULTS

Vaccination against SARS-CoV-2 is needed for protection against severe infection. Skin reactions may arise with SARS-CoV-2 infections. Short-term general immune reactions and skin reactions are also possible upon SARS-CoV-2 vaccination; however, they recur in only a proportion of patients during follow-up vaccinations. Initial reports of anaphylaxis after vaccination fueled public fear. On the other hand, more recent epidemiologic data do not show a substantially increased anaphylaxis risk compared with other vaccines. Fear-related reactions may be essential for many "anaphylaxis" reports. In Germany, the flow chart developed by Paul-Ehrlich-Institut (PEI) and Robert-Koch-Institut (RKI) together with the allergological societies helps to care for patients with suspected "allergy history" safely and effectively. Through this, patients with increased risk of anaphylaxis to SARS-CoV-2 vaccines and their ingredients (e.g., polyethylene glycol (PEG), polysorbate 80) are identified. However, since only small amounts of these excipients are contained in mRNA vaccines, even some PEG-allergic patients can tolerate the vaccination. In Germany, an allergy test-guided procedure is recommended for high-risk patients, including an allergy history, prick tests, intradermal and basophil activation tests, and, if necessary, provocation tests. This also appears effective for anxiety reduction in patients with vaccination skepticism. To date, all of our patients have been able to be vaccinated with SARS-CoV-2 vaccines without the occurrence of significant reactions.

CONCLUSION

Many initial concerns about unexpected side effects of SARS-CoV-2 vaccination have not been confirmed. The flowchart and, in the case of suspicion of hypersensitivity, an allergy test-guided risk assessment helps to reduce patients' fear of vaccination and enables safe vaccination.

Informations de copyright

© Dustri-Verlag Dr. K. Feistle.

Déclaration de conflit d'intérêts

The authors declare no conflict of interest. Table 1.Lessons on SARS-CoV-2 and allergy in recent years. Skin reactions associated with SARS-CoV-2 infectionCommon maculopapular exanthema, papulovesicular exanthema, acute urticaria, and vascular reactionsHypersensitivity reactions to drugs used to control SARS-CoV-2 infectionRare, no typical triggers of hypersensitivity reactionsSide effect rate of SARS-CoV-2 vaccinationLow and overall comparable to other vaccinesCommon general adverse reactions to SARS-CoV-2 vaccination As with other vaccines, predominantly flu-like symptomsSkin reactions after SARS-CoV-2 vaccinationIn particular, local reactions, urticaria and morbilliform exanthema, also worsening of chronic inflammatory skin diseases, pityriasis rosea and zoster. Recurrence with follow-up vaccination < 50%.Severe complications after SARS-CoV-2 vaccination mRNA vaccinesIncreased risk of myocarditis and pericarditis, mostly mild and no contraindication for follow-up vaccination after healing. Vector vaccines: thrombosis at atypical sites especially in younger patients, and questionable Guillain-Barré syndrome, both contraindications for these vaccinesRisk of anaphylaxis to vaccinationInitially many individual cases of anaphylaxis reported, significantly increased risk of anaphylaxis feared, incidence now equal to or not substantially above that of other vaccines. Frequently women, allergies often reported, previous anaphylaxisVaccination in “allergic” patientsProcedure according to flow chart (Figure 2)Vaccination in patients with contact sensitization to PEGNo evidence of PEG immediate type allergy; we have advised patients to vaccinate and have several reports of good tolerabilityAllergy testing prior to vaccinationIn Germany/Europe if there is evidence of vaccine hypersensitivity or PEG allergy. In the U.S., increasingly vaccination without prior allergy testing on an emergency standby basisAllergy testing methodsDepending on availability and experience, skin prick test, intradermal test if necessary, basophil activation test and provocation tests with vaccine residues and adjuvants.Vaccination of PEG-allergic patientsPossible after allergy diagnostics, after appropriate documented information and consent of the patient under appropriate monitoring and emergency preparedness. Figure 1.Adverse reactions frequently reported to the Paul Ehrlich Institute after vaccination with Spikevax (Moderna), Vaxzevria (AstraZeneca), Comirnaty (BioNTech/Pfizer), and the COVID-19 vaccine Janssen. Percent frequencies are given (percentage of the number of adverse reactions reported in each case out of the total number of adverse reactions reported after administration of each COVID-19 vaccine). Source: https://www.pei.de/DE/newsroom/dossier/coronavirus/coronavirus-inhalt.html, Safety-Report-27-12-to-31-07-21.Figure 2.Updated flowchart on the procedure in patients with positive allergy history before COVID-19 vaccination.