Experts Advise on Rare Severe Allergic Reactions to COVID Vaccines

By Reuters Staff

July 06, 2021

NEW YORK (Reuters Health) - Anaphylactic reactions to SARS-CoV-2 mRNA vaccines may occur but are rare, and the benefits of vaccination outweigh the risks, according to an expert panel that has developed recommendations on diagnosis and management.

Concerns for anaphylaxis may hamper SARS-CoV-2 immunization efforts and contribute to vaccine hesitancy and must be weighed against the life-saving and disease-mitigating benefits of SARS-CoV-2 vaccination, the panel writes in The Journal of Allergy and Clinical Immunology: In Practice.

Through the first month after the U.S. Food and Drug Administration (FDA) issued an emergency use authorization for two mRNA vaccines, the federal health officials described 66 anaphylaxis events in more than 17.5 million vaccinations, or roughly 3.7 events per million.

One large U.S. academic medical center reported 16 cases of anaphylaxis among 64,900 vaccinations (250 cases per million vaccinations) over a two-month period.

Until now, there have been no uniform recommendations on assessment and management of individuals with a known or suspected allergy to SARS-CoV-2 vaccines or the excipients.

Therefore, a multi-disciplinary, international panel of experts came together to systematically review the evidence and develop recommendations regarding anaphylaxis after SARS-CoV-2 vaccination, polyethylene glycol (PEG) and polysorbate allergy, and accuracy of allergy testing for SARS-CoV-2 vaccine allergy.

They report that the incidence of SARS-CoV-2 vaccine anaphylaxis is 7.91 cases per million vaccinations, the prevalence of PEG allergy 103 cases per million, and the sensitivity for PEG skin testing is poor though specificity is high.

Among the panel's conclusions and recommendations:

- For patients with no history of a severe allergic reaction to a SARS-CoV-2 vaccine or its excipients, the risk of SARS-CoV-2 vaccine-induced anaphylaxis is "very rare" and vaccination over no vaccination is recommended based on this risk.

- For patients with a history of a severe allergic reaction, including anaphylaxis, unrelated to a SARS-CoV-2 vaccine or excipient, the requirement for additional observation beyond standard wait time provides a minimal absolute-risk reduction in severe allergic reaction outcomes and may also contribute to vaccine hesitancy. "Therefore, we suggest against prolonged observation in those with a history of severe allergic reactions unrelated to a SARS-CoV-2 vaccine or excipient," the panel said.

- In patients with no history of a severe allergic reaction, including anaphylaxis, to SARS-CoV-2 vaccines or its excipients, the panel recommends against vaccine or vaccine excipient testing prior to vaccination in an attempt to predict the rare individual who will have a severe allergic reaction to vaccination.

- The panel recommends against routinely performing skin or in vitro testing using SARS-CoV-2 vaccines or excipients outside of the research setting for the purpose of vaccine withholding, given such testing has unknown sensitivity/specificity in predicting severe allergic reactions, including anaphylaxis, to SARS-CoV-2 vaccines.

- The panel recommends a shared decision-making paradigm of care favoring vaccination through full or graded dosing (with or without additional observation time post-vaccination) or changing vaccine platforms to another agent over no vaccination because there is no single best approach to assessment and management of the patient with a suspected SARS-CoV-2 mRNA or adenovirus vector vaccine reaction, or the patient with an allergy to an excipient in either of these vaccines who has not yet been vaccinated.

- In patients with suspected immediate allergic reaction to SARS-CoV-2 vaccine whose standard schedule requires more than one dose, the panel recommends referral to an allergist for assessment of additional vaccination over no vaccination/vaccination being withheld.

- In patients with a suspected or confirmed but remote past medical history of reaction to a SARS-CoV-2 vaccine excipient, referral to an allergist for assessment of additional vaccination over no vaccination/vaccination being withheld is advised.

- In patients with a definite/confirmed recent allergic reaction to SARS-CoV-2 vaccine and/or excipient, the panel recommends referral to an allergist for assessment of additional vaccination over no vaccination/vaccination being withheld.

- SARS-CoV-2 mRNA or adenovirus vector vaccines should be administered in a setting equipped to manage anaphylaxis under the supervision of personnel trained in the recognition and management of anaphylaxis.

- The panel advises against routine H1-antihistamine or systemic corticosteroid pre-medication prior to vaccination as it is based on low-certainty evidence in preventing anaphylaxis, and theoretically corticosteroid pre-medication could diminish the immune response.

"As this is the first experience with these vaccines, this is intended to be a living document that will require periodic updating due to still emerging needs assessment, including further research data on the nature of vaccine-associated reactions and the necessity of potential risk-assessment measures," the panel says.

This work had no specific funding.

SOURCE: https://bit.ly/3wQx0ii The Journal of Allergy and Clinical Immunology: In Practice, online June 18, 2021.

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as:

processing....