D1.422 - A service review of the complex COVID-19 vaccination service

Mass vaccination for the SARS-CoV-2 virus was associated with considerable concerns around side-effects, ‘reactions’, and toxicity amongst both potential recipients and healthcare workers. In the UK, allergy services played a key role in providing specialist guidance and (where needed) hospital-based vaccination, and here we report our experiences as the regional provider for Sussex, on the south coast of the United Kingdom, from March 2021 onwards.

Data was extracted from our patient database. We considered demographics, reasons for referral and vaccination type provided. The outcome of vaccination during the 30-minute observation period was classified as ‘uneventful’ or ‘symptomatic’. Symptomatic vaccination events were subclassified as follows: ‘immediate non-allergic’ (e.g. vasovagal, anxiety); ‘immediate urticaria’ (cutaneous symptoms such as itching, wheals, swelling); ‘isolated upper airway’ (upper airway symptoms without wider features of anaphylaxis); ‘vaccine allergy’ (true multi-system anaphylaxis).

Thousands of enquiries were received and mostly answered with advice and guidance to proceed as usual in the community. We provided 305 hospital-based vaccinations for patients identified as unsuitable for community services. The main indications for hospital-based vaccination were: previous immediate symptoms following vaccination; reported drug allergy; chronic spontaneous urticaria (CSU) (often referred as ‘allergic reactions’).

254 (83%) vaccinations were uneventful. 51 (17%) provoked symptoms of which 24 (47%) were immediate non-allergic, 19 (37%) immediate urticaria, 7 (14%) isolated upper airway and 1 (2%) true vaccine allergy. Most patients with immediate urticaria had underlying CSU. Several patients with known polyethylene glycol (PEG) allergy were referred; only 1 new case was identified. All tolerated an mRNA alternative. Patients with isolated upper-airway symptoms were generally given adrenaline, but emerging data suggests that the majority probably had a non-allergic issue. Only 1 patient experienced true multi-system anaphylaxis.

The relatively high rate of immediate symptoms in our service supports the importance of a hospital-based complex vaccination service. However, true ‘allergic’ reactions to these vaccinations appears to be very rare, with most immediate symptoms reflecting non-allergic issues or exacerbation of pre-existing CSU. The single most important function of the service was the provision of guidance and reassurance.