Novel ‘hub-and-spoke’ model accelerates allergy assessments before COVID-19 vaccinations

A clinical “hub-and-spoke” model expanded allergy assessments and increased the number of safe COVID-19 vaccinations in Hong Kong, according to a study presented at the European Academy of Allergy and Clinical Immunology Hybrid Congress.

The model also revealed the crucial role that allergists play in combatting vaccine hesitancy, Valerie Chiang, MBBS, of the division of clinical immunology in the department of pathology at Queen Mary Hospital in Hong Kong, said during the presentation.

In February 2021, Hong Kong launched its territory-wide COVID-19 vaccination program and vaccine allergy safety (VAS) consensus statements. The program cautioned patients with histories of anaphylaxis or severe immediate reactions to multiple classes of drugs that they could require an assessment from an allergist before vaccination.

“However, overwhelming inappropriate referrals combined with a lack of allergy specialists led to huge waiting times, which aggravated public dissatisfaction and vaccine confidence,” Chiang said.

Designed by the researchers, the fast track multidisciplinary triage pathway allowed nurses and non-allergists at seven “spoke” clinics founded across Hong Kong based on geographic clusters to participate in allergy assessments with leadership and support from an allergist-led “hub” clinic.

“The primary objective was to empower individual spoke clinics to independently provide pre-vaccination assessment with support from the hub,” Chiang said.

Based on a cohort that included 2,725 unvaccinated patients evaluated between March and August 2021, the researchers found three key clinical findings.

“Firstly, the hub-and-spoke model was both safe and effective in improving vaccination rates,” Chiang said.

Providers in the model recommended 85.3% of these patients to proceed with vaccination. None of these patients reported any allergic reactions after vaccination, and all of them remained eligible for subsequent vaccinations.

A subgroup analysis of the hub and West Hong Kong spoke clinic, which saw the largest number of patients (n = 1,411), found that 83.5% of these patients safely received their first dose of the COVID-19 vaccine after assessment.

“Were it not for this VAS initiative, these patients would have been ineligible for COVID-19 vaccination under local guidance,” Chiang said.

Second, the allergists in the program recommended significantly more patients for COVID-19 vaccination than the non-allergists in the program (OR = 21.58; 95% CI, 10.16-45.82).

Chiang attributed these differences to more confidence among the allergists in their clinical judgment as well as their prior experience with the safety of COVID-19 vaccines, enabling a less cautious approach than the non-allergists.

Finally, the patients assessed by allergists were significantly more likely to get COVID-19 vaccines than those assessed by non-allergists (OR = 4.18; 95% CI, 2.81-6.21).

Chiang attributed these differences to allergist experience in patient counseling and in providing guidance about conditions that are not related to COVID-19 vaccine allergies, including allergic rhinitis, asthma, atopic dermatitis, food allergies and chronic spontaneous urticaria.

“These conditions are often misunderstood to be related to vaccine allergy,” Chiang said. “It is likely that the hub was also able to address these concerns more holistically and provide advice on the management of these conditions.”

The researchers concluded that the hub-and-spoke model successfully aided the COVID-19 vaccination campaign, with wait times for assessments reduced from 5 years to 3 months.

Also, the researchers said the study proves that allergists have a crucial role in mitigating vaccine hesitancy as they bolstered public confidence in the safety of COVID-19 vaccines, although the differences in results between the allergist and non-allergist clinics merit further study.

“We show promising results that can empower our colleagues to improve promoting vaccine allergy safety in a true interdisciplinary effort,” Chiang said.

“This study has potential far-reaching changes not only in COVID-19 vaccination,” she continued. “We are hopeful the hub-and-spoke model can be similarly assimilated to other allergist integrated services in the future.”