The Prevalence of Immediate Hypersensitivity Reactions to the BNT162b2 mRNA Vaccine against SARS-CoV-2: Data from the Vaccination Campaign in a Large Academic Hospital.

The anti-SARS-CoV-2 vaccination has probably been the most effective tool for preventing the infection and negative outcomes of the COVID-19 disease, and therefore for interrupting the pandemic state. The first licensed SARS-CoV-2 vaccine was BNT162b2, an mRNA vaccine that has been widely used since the earliest stages of the global vaccination campaign. Since the beginning of the vaccination campaign, some cases of suspected allergic reactions to BNT162b2 have been described. Epidemiological data, however, have provided reassuring results of an extremely low prevalence of these hypersensitivity reactions to anti-SARS-CoV-2 vaccines. In this article, we describe the results of a survey carried out through the use of a questionnaire, administered to all the health personnel of our university hospital after the first two doses of the BNT162b2 vaccine, which investigated the development of adverse reactions after a vaccination. We analyzed the responses of 3112 subjects subjected to the first dose of the vaccine; among these, 1.8% developed symptoms compatible with allergic reactions and 0.9% with clinical manifestations of possible anaphylaxis. Only 10.3% of the subjects who had allergic reactions after the first injection experienced similar reactions after the second dose and none of them experienced anaphylaxis. In conclusion, the anti-SARS-CoV-2 vaccination is rarely associated with severe allergic reactions and the second dose of vaccine is safe for this group of patients.

Polyethylene Glycol and Polysorbate 80 Skin Tests in the Context of an Allergic Risk Assessment for Hypersensitivity Reactions to Anti-SARS-CoV-2 mRNA Vaccines.

Concern has arisen about hypersensitivity reactions in patients with allergic reactions to drugs containing polyethylene glycol (PEG) or polysorbate 80 (PS80), excipients of currently available anti-SARS-CoV-2 mRNA vaccines. However, the actual utility of PEG and PS80 skin allergy testing is currently still debated. We retrospectively analyzed all cases of patients on whom we performed allergometric skin tests for PEG and PS80 in the context of a pre-vaccination screening (for patients with multiple hypersensitivity reactions to drugs for which these excipients were among the suspected agents) or following suspected hypersensitivity reactions to anti-SARS-CoV-2 vaccines. A total of 134 tests were performed for PEG and PS80, eight of which produced uninterpretable results (due to dermographism or non-specific reactions). Of the remaining 126 cases (85 pre-vaccinal and 41 post-vaccine reactions), 16 (12.7%) were positive for PEG and/or PS80. Stratifying by clinical indication, there were no statistically significant differences in the proportion of positive tests between patients evaluated in the context of the pre-vaccination screening and those evaluated after a vaccine reaction (10.6% vs. 17.1%, respectively, p = 0.306). Allergometric skin tests for PEG and PS80 in our case series resulted positive in an unexpectedly high proportion of patients, suggesting that testing for allergy to these two excipients should not be ignored in case of reasonable clinical suspicion.

Desensitization Protocols for Anti-SARS-CoV-2 Vaccines in Patients with High Risk of Allergic Reactions.

Vaccines for SAR-CoV-2 are the most effective preventive treatment able to reduce the risk of contracting the infection and experiencing worse outcomes whenever the infection is contracted. Despite their rarity, hypersensitivity reactions to the anti-SARS-CoV-2 vaccine have been described and could become the reason not to complete the vaccination. Desensitization protocols for other vaccines have been described and validated, while the use of this approach for anti-SARS-CoV-2 vaccines is still anecdotal. We herein describe our experience with 30 patients with previous allergic reactions to anti-SARS-CoV-2 vaccines or to any of their excipients, proving that they are effective and safe; only two patients experienced hypersensitivity reaction symptoms during the desensitization procedure. Moreover, in this article, we propose desensitization protocols for the most common anti-SARS-CoV-2 vaccines.

Successful SARS-CoV-2 vaccine allergy risk-management: The experience of a large Italian University Hospital.

BACKGROUND: Novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) vaccines have been approved recently, and public concern regarding the risk of anaphylactic reactions arose after a few cases during the first days of mass vaccination. Polyethylene glycol (PEG) has been suggested as the most probable culprit agent for allergic reactions. OBJECTIVE: We describe the allergy work-up protocol implemented for the vaccination campaign in our Center, aiming to allow the greatest number of people to be vaccinated safely. METHODS: The protocol included the self-report of a history of suspected drug or vaccine allergies, and subsequent teleconsultation and allergometric tests for PEG and Polysorbate 80 (PS80). A desensitizing protocol of vaccine administration was applied to patients sensitized only to PS80, and to those with a suspect allergic reaction after the first vaccine dose. RESULTS: 10.2% (414 out of 4042) of the entire vaccine population have been screened: only one patient resulted allergic to PEG and therefore excluded from the vaccination. Another patient was sensitized to PS80 only and safely vaccinated applying the desensitizing protocol. Seven subjects without a previous history of allergic disease experienced suspect hypersensitivity reactions to the first administered dose: one of them resulted allergic to PEG and was excluded from the second dose, while the others safely completed the vaccination with the desensitizing protocol. CONCLUSION: A careful allergological risk-assessment protocol significantly reduces the number of patients who would have avoided SARS-CoV-2 vaccination for their allergies and to effectively identify and manage those rare patients with sensitization to PEGs and/or PS80.

Allergy clinics in times of the SARS-CoV-2 pandemic: an integrated model.

BACKGROUND: Almost the entire World is experiencing the Coronavirus-Disease-2019 (COVID-19) pandemic, responsible, at the end of May 2020, of more than five million people infected worldwide and about 350,000 deaths. In this context, a deep reorganization of allergy clinics, in order to ensure proper diagnosis and care despite of social distancing measures expose, is needed. MAIN TEXT: The reorganization of allergy clinics should include programmed checks for severe and poorly controlled patients, application of digital medicine service for mild-to-moderate disease in well-controlled ones, postponement of non urgent diagnostic work-ups and domiciliation of therapies, whenever possible. As far as therapies, allergen immunotherapy (AIT) should not be stopped and sublingual immunotherapy (SLIT) fits perfectly for this purpose, since a drug home-delivery service can be activated for the entire pandemic duration. Moreover, biologic agents for severe asthma, chronic spontaneous urticaria and atopic dermatitis should be particularly encouraged to achieve best control possible of severe disease in times of COVID-19 and, whenever possible, home-delivery and self-administration should be the preferred choice. CONCLUSION: During COVID-19 pandemic, allergists have the responsibility of balancing individual patients' needs with public health issues, and innovative tools, such as telemedicine and digital medicine services, can be helpful to reduce the risk of viral spreading while delivering up-to-date personalized care.