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. 2022 Jan;15(1):100622.
doi: 10.1016/j.waojou.2021.100622. Epub 2021 Dec 20.

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

Valerie Chiang  1 , Sabrina Wing Shan Mok  2 , June King Chi Chan  2 , Wai Yan Leung  3 , Carmen Tze Kwan Ho  3 , Elaine Y L Au  1 , Chak Sing Lau  3 , Tak Hong Lee  2 , Philip Hei Li  3
Affiliations

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

Valerie Chiang et al. World Allergy Organ J. 2022 Jan.

Abstract

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.

Keywords: Allergy; Anaphylaxis; COVID-19; Hong Kong; Hypersensitivity; Safety; Vaccine.

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Conflict of interest statement

The authors report no competing interests.

Figures

Fig. 1
Fig. 1
Venn diagram of patients attending for pre-vaccine precautions and recommended to defer vaccination
Fig. 2
Fig. 2
Monthly number of referrals accepted, referrals rejected and patients seen at HKWC VAS Clinic from March to June 2021
Fig. 3
Fig. 3
Allergist-confirmed etiologies of confirmed and suspected anaphylaxis referrals seen at HKWC VAS Clinic (n = 178)
See this image and copyright information in PMC

References

    1. Li P.H., Wagner A., Rutkowski R., et al. Vaccine allergy: a decade of experience from 2 large UK allergy centers. Ann Allergy Asthma Immunol. 2017;118(6):729–731. - PubMed
    1. Wong M.C.S., Wong E.L.Y., Huang J., et al. Acceptance of the COVID-19 vaccine based on the health belief model: a population-based survey in Hong Kong. Vaccine. 2021;39:1148–1156. - PMC - PubMed
    1. Chiang V., Leung A.S.Y., Au E.Y.L., et al. Consensus statements on the approach to COVID-19 vaccine allergy safety in Hong Kong. Front Allergy. 2021;2(32) - PMC - PubMed
    1. Vaccination Programme at Clinics under the Vaccination Subsidy Scheme. 2021. https://www.covidvaccine.gov.hk/pdf/VSS_DoctorsGuide.pdf Available from:
    1. Department of Health. Report on the Safety Monitoring of COVID-19 Vaccines in Hong Kong. 2021. https://www.drugoffice.gov.hk/eps/do/en/doc/Safety_Monitoring_of_COVID-1...