RESUMO
BACKGROUND: Concerns about new COVID-19 vaccines played a key role in vaccine hesitancy and hampered population uptake. Hong Kong initiated a Vaccine Allergy Safety Track (VAS-Track) program to assess potential COVID-19 vaccine-associated allergies. A 'Hub-and-Spoke' model of predominately non-specialists supported by the allergist hub was established to meet overwhelming demand despite limited specialists. OBJECTIVE: To assess the cost-effectiveness of VAS-Track as a pre- and post-vaccination assessment service for individuals potentially at high risk of COVID-19 vaccine-related allergy. METHODS: An individual-level decision-analytical model was constructed using data from VAS-Track participants supplemented by published estimates. Analyses were from a health service provider perspective over 12 months. We calculated the incremental cost-effectiveness ratio (ICER) to estimate the cost per quality-adjusted life years (QALYs) gained. Willingness-to-pay threshold was based on local GDP per capita (US$ 49,590). Sensitivity analyses examined robustness of findings. RESULTS: Cost-effectiveness varied widely across age groups. VAS-Track was cost-saving for older adults (dominant strategy for age ≥ 50) compared with standard practice across a range of sensitivity analyses. VAS-Track was not cost-effective for younger groups (age 18-49: ICER: US$ 410,914/QALY for pre-vaccination and US$ 213,786/QALY for post-vaccination assessments). Infection rate, cost of treating severe infection, and vaccination rate were most influential on cost-effectiveness estimates. CONCLUSION: VAS-Track was cost-effective both as a pre- and post-vaccination assessment service for adults over 50. The 'Hub-and-Spoke' model using non-specialists with limited allergy specialist resources to provide vaccine allergy assessment services would provide high economic value compared with usual care for adults aged 50 and over.
RESUMO
BACKGROUND: Misdiagnosed vaccine-related "allergies" lead to unnecessary vaccine deferrals and incomplete vaccinations, leaving patients unprotected against COVID-19. To overcome limitations and queues for Allergist assessment, the "VAS-Track" pathway was developed to evaluate patients via a multi-disciplinary triage model including nurses, non-specialists, and Allergists. OBJECTIVE: We assessed the effectiveness and safety of VAS-Track and evaluate its real-world impact in terms of vaccination rates and COVID-19 protection. METHODS: Patients referred to VAS-Track between September 2021 and March 2022 were recruited. Subgroup analysis was performed with prospective pre- and post-clinic antibody levels. RESULTS: Nurse-assisted screening identified 10,412 (76%) referrals as inappropriate. 369 patients were assessed by VAS-Track. Overall, 100% of patients were recommended to complete vaccination and 332 (90%) completed their primary series. No patients reported any significant allergic reactions following subsequent vaccination. Vaccination completion rates between patients seen by non-specialists and additional Allergist review were similar (90% vs. 89%, p = 0.617). Vaccination rates were higher among patients with prior history of immediate-type reactions (odds ratio: 2.43, p = 0.025). Subgroup analysis revealed that only 20% (56/284) of patients had seropositive COVID-19 neutralizing antibody levels (≥ 15 AU/mL) prior to VAS-Track, which increased to 92% after vaccine completion (pre-clinic antibody level 6.0 ± 13.5 AU/mL vs. post-clinic antibody level 778.8 ± 337.4 AU/mL, p > 0.001). CONCLUSIONS: A multi-disciplinary allergy team was able to streamline our COVID-19 VAS services, enabling almost all patients to complete their primary series, significantly boosting antibody levels and real-world COVID-19 protection. We propose similar multidisciplinary models to be further utilized, especially in the settings with limited allergy services.
RESUMO
BACKGROUND: Hong Kong started its coronavirus disease 2019 (COVID-19) vaccination program in February 2021. A territory-wide Vaccine Allergy Safety (VAS) clinic was set up to assess individuals deemed at "higher risk" of COVID-19 vaccine-associated allergies. A novel "hub-and-spoke" model was piloted to tackle the overwhelming demand of services by allowing nonallergists to conduct assessment. OBJECTIVE: To evaluate the outcomes of the VAS hub-and-spoke model for allergy assessment. METHODS: Records of patients attending the VAS hub-and-spoke Clinics between March and August 2021 were reviewed (n = 2725). We studied the overall results between the Hub (allergist led) and Spoke (nonallergist led) Clinics. The Hub and the Hong Kong West Cluster Spoke Clinic were selected for subgroup analysis as they saw the largest number of patients (n = 1411). RESULTS: A total of 2725 patients were assessed under the VAS hub-and-spoke model. Overall, 2324 patients (85.3%) were recommended to proceed with vaccination. Allergists recommended significantly more patients for vaccination than nonallergists (odds ratio = 21.58; P < .001). Subgroup analysis revealed that 881 of 1055 (83.5%) patients received their first dose of COVID-19 vaccination safely after assessment. Among those recommended vaccination, more patients assessed by allergists received their first dose of vaccination (odds ratio = 4.18; P < .001). CONCLUSION: The hub-and-spoke model has proven to be successful for the vaccination campaign. This study has illustrated the crucial role of allergists in countering vaccine hesitancy. Results from the study revealed considerable differences in outcomes between allergist-led and nonallergist-led clinics. Precise reasons for these differences warrant further evaluation. We are hopeful that the hub-and-spoke model can be similarly adapted for other allergist-integrative services in the future.