Experience of the first 1127 COVID-19 Vaccine Allergy Safety patients in Hong Kong-Clinical outcomes, barriers to vaccination, and urgency for reform

Introduction: Hong Kong has had a low incidence of COVID-19 vaccine related anaphylaxis, partly due to its Vaccine Allergy Safety (VAS) guidelines for screening those at higher risk of COVID-19 vaccine-associated allergic reactions. We characterize the initial experience of the VAS clinics, as well as the impact of unnecessary referrals to the vaccination program. Methods: All patients attending the VAS Clinics of the public and private health services between February and June 2021 were reviewed. Results: Out of 1127 patients assessed at VAS clinics, 1102 (97.8%) patients were recommended for vaccination. Out of those contacted, more than 80% (450/558) received vaccination successfully; the remaining had not yet booked their vaccinations. The majority (87.5%) of patients not recommended was due to potential excipient allergies. Males were significantly more likely to be recommended (OR = 5.822, 95% CI = 1.361-24.903, p = 0.007), but no other features were associated with recommendation for vaccination. Almost half (45.1%) of public service referrals were rejected due to insufficient information or incorrect indications for referral. The majority of cases (56.2%) of patients referred for suspected anaphylaxis did not fulfil diagnostic criteria. Discussion: COVID-19 vaccination is very safe and 98% of high-risk patients were recommended for vaccination. Barriers to VAS include a high proportion of inappropriate referrals, inaccurate diagnoses of anaphylaxis and inability to diagnose excipient allergies. Our data validates that a prior history of COVID-vaccine unrelated anaphylaxis should be removed as a precaution for vaccination. Closer collaborations between primary care and allergy specialists and changes in pharmaceutical legislation should be made a priority to promote vaccination uptake.

Automated summary

Hong Kong has a low incidence of COVID-19 vaccine related anaphylaxis, due in part to its Vaccine Allergy Safety (VAS) guidelines. The majority of patients assessed at VAS clinics were recommended for vaccination, but there were still unnecessary referrals that caused some rejections in the public vaccination program.