key: cord-0935851-cpagezii authors: Chiang, Valerie; Saha, Chinmoy; Yim, Jackie; Au, Elaine; Kan, Andy; Hui, Harris; Li, Tin Sum; Lo, Whitney; Hong, YuhDong; Ye, Jiaxi; Ng, Carmen; Ko, Welchie; Ho, Carmen; Lau, Chak Sing; Quan, Jianchao; Li, Philip title: Allergists and COVID-19 Vaccine Allergy Safety: A Pilot Study “Hub-and-Spoke” Model for Population-Wide Allergy Service date: 2022-05-20 journal: Ann Allergy Asthma Immunol DOI: 10.1016/j.anai.2022.05.011 sha: 91834609ad5f4faf24df6bc4f14fd05943a82a80 doc_id: 935851 cord_uid: cpagezii Background: Hong Kong started its COVID-19 vaccination program in February 2021. A territory-wide VAS (Vaccine Allergy Safety) 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 non-allergists to conduct assessment. Objective: This study aims 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 (non-allergist-led) Clinics. The Hub and the HKWC 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 non-allergists (OR=21.58, p<0.001). Subgroup analysis revealed that 881/1055 (83.5%) of patients received their first dose of COVID-19 vaccination safely following assessment. Among those recommended vaccination, more patients assessed by allergists received their first dose of vaccination (OR=4.18, p<0.001). 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 showed considerable differences in outcomes between allergist-led and non-allergist clinics. Precise reasons for these differences warrant further examination. We are hopeful the Hub-and Spoke model can be similarly adapted for other allergist-integrative services in the future. Vaccination remains the most promising strategy to end the coronavirus 2019 (COVID-19) pandemic. Hong Kong started its territory-wide COVID-19 vaccination program in February 2021, providing its citizens with two vaccine options: the Sinovac CoronaVac and Fosun Pharma BioNTech Comirnaty. Hong Kong citizens can freely choose between the two vaccines for their primary inoculations, with surplus doses purchased for both formulations of vaccines. Both vaccines became available around the same time (within a month) of each other. Although vaccine-associated allergic reactions and anaphylaxis are extremely rare, the overall vaccine acceptance rate by the public was below 40% even before the commencement of COVID-19 vaccinations in Hong Kong, largely attributed to the lack of trust in novel vaccine platforms and manufacturers 1, 2 . Given the novel nature of mRNA vaccines and initial global concerns over vaccine-related allergic reactions, worldwide health authorities took a conservative approach in protecting individuals who may be at higher risk of COVID-19 vaccine-associated allergy 3, 4 . Similarly, the Hong Kong Institute of Allergy (HKIA) established its first territory-based COVID-19 Vaccine Allergy Safety (VAS) Consensus Statements to define individuals at higher risk of potential COVID-19 vaccine-related allergies. Due to the initial fear of potential excipient associated allergies, patients with history of anaphylaxis or severe, immediate-type allergic reactions to multiple classes of drugs/foods were cautioned and may require allergist assessment prior to COVID-19 vaccination 5 . A territory-wide VAS Clinic was set up for pre-vaccination evaluation of these at-risk individuals. However, this VAS clinic had limited capacity as there was only one Specialist in Immunology & Allergy working in Hong Kong's public healthcare system. Despite clear guidance for vaccination, many patients were inappropriately referred for specialist assessment due to anxiety or misdiagnosis of previous allergic history 6 . Given Hong Kong's extreme shortage of allergists, the VAS Clinic was quickly overwhelmed by an exponential increase in referrals that reached over 2500 new referrals per month 6, 7 . Coupled with growing concerns of vaccine safety amid media reports of suspected COVID-19 vaccine-associated anaphylaxis, these long waiting times for VAS assessment led to delayed vaccinations and growing vaccine hesitancy among the general population 8 . To tackle the overwhelming demand for vaccine allergy services, a novel VAS "Huband-Spoke" model was piloted to allow non-allergist doctors to conduct pre-vaccination allergy assessment. Under this Hub-and-Spoke Model, seven new individual "Spoke" Clinics were set up across Hong Kong. These individual "Spoke" Clinics were run by non-allergists, who were trained and supervised by the allergist-led "Hub". The Hub continued to see patients for pre-vaccination allergy assessment, but patients with excessive waiting times were redirected to their respective Spokes based on the patients' geographical location ( Figure 1 ). The primary objective was to empower individual Spoke Clinics to independently provide pre-vaccination assessment with support from the Hub. This study aims to evaluate the outcomes and effectiveness of the VAS Hub-and-Spoke Model for pre-vaccination allergy assessment. We studied the overall rate of vaccination as well as comparative rates between the Hub (allergist-led) and Spoke (non-allergist-led) Clinics. We also conducted a subgroup analysis to compare the actual rate of COVID-19 vaccination and allergic reactions following assessment at Hub and Spoke Clinics. The Hospital Authority is the sole publicly funded health care provider in Hong Kong with its services were retrieved and reviewed. Only complete patient records were included for analysis and all data was anonymized after data extraction. Extracted clinic data included age, sex, indicators for referral, allergy investigations performed and outcome of allergist evaluation (if deemed at higher risk of COVID-19 vaccine-associated allergic reactions and whether to proceed with vaccination or not). Individuals at higher risk of potential COVID-19 vaccine-related allergies were defined as those with history of anaphylaxis or severe, immediate-type allergic reactions to multiple classes of drugs/foods were cautioned and may require allergist assessment prior to COVID-19 vaccination 5 . Inappropriate referrals were defined as insufficient information or absence of such criteria. The Hub and the HKWC Spoke Clinic were selected for subgroup analysis as they saw the largest number of patients. All patients who attended these two clinics were followed-up by telephone at least one month after Hub or Spoke Clinic assessment, and had their vaccination records confirmed via the Hospital Authority's Computer Management System. For subgroup analysis, additional information was collected by telephone interview, including other existing medical co-morbidities, smoking status, history of urticaria, history of drug allergy as well as any allergic reactions following COVID-19 vaccination. Rates of COVID-19 vaccination were compared between patients attending the Hub and HKWC Spoke Clinic. Categorical variables were expressed as number (percentage) and continuous variables as median (range) where appropriate. Logistic regression was used to calculate the odds ratios of vaccine recommendation and actual vaccination respectively associated with the Hub and Spoke Clinics. A pvalue of less than 0.05 was considered statistically significant. STATA version 16 (StataCorp LLC, TX) were used for all analyses. Informed consent was waived (because all data were anonymized and collected retrospectively) and approved by the institutional review board of the University of Hong Kong and Hospital Authority Hong Kong West cluster. Table 1 and Figure 2 . There were no significant demographic differences between patients seen at the Hub or any Spokes Clinics. Allergists recommended significantly more patients for COVID-19 vaccination than non-allergists Table 1 ). This finding was consistent when comparing the Hub with individual Spoke Clinics (data not shown). More than 83% of followed-up patients proceeded and received first dose COVID-19 vaccination Table 2) . Establishing the COVID-19 VAS program was paramount to boosting public confidence in vaccination and kickstart the vaccination campaign in Hong Kong. The recommendations set out by HKIA in early 2021 were successful at keeping a low incidence of allergic events to counter local vaccine hesitancy, largely driven by fears of vaccine-related allergic reactions. Despite these recommendations, there remained an overwhelming number of referrals which the VAS clinic could not handle 6 . This novel VAS Hub-and-Spoke model was therefore established and allowed for non-specialists to participate in evaluating patients who were deemed "higher risk" for developing COVID-19 vaccine-associated allergies. This study found that the Hub-and-Spoke model was safe and effective for pre-vaccine allergy assessment, but there were significant differences between the Hub and Spoke Clinics. Overall, our Hub-and-Spoke model enabled 2725 patients to be assessed and 2324 (85%) were recommended for vaccination. The longest waiting appointment time for pre-vaccine assessment fell from over five years (scheduled prior to establishment of the Hub-and-Spoke Model) to less than three months. Were it not for this VAS initiative, these patients would have been ineligible for COVID-19 vaccination under local guidance. More importantly, from our subgroup analysis, more than 83% of these recommended patients successfully received their first dose of COVID-19 vaccines. Given the severe shortage of allergists in Hong Kong, it is evident that our Hub-and-Spoke model was both safe and effective in improving vaccination rates, with no patients reporting any subsequent allergic reactions, and all remaining eligible for subsequent COVID-19 vaccinations. Furthermore, the effects of this successful Hub-and-Spoke Model were significantly more far-reaching than just the 2725 patients assessed. By ensuring low incidences of vaccine-related allergic events, we were able to bolster public confidence in the safety of COVID-19 vaccines. This study specifically highlights the impact of specialist-level expertise, particularly in Immunology and Allergy. Hong Kong's experience in COVID-19 VAS exemplifies yet another aspect of Immunology and Allergy in which specialist-level input is necessary. Allergists are often thought to manage only rare and highly specialized diseases, but this study highlights their role in tackling population health such as widespread vaccine hesitancy during an urgent global vaccination campaign. Our results also demonstrate the importance of multi-disciplinary collaboration, especially between internists and family physicians, and highlights the feasibility of further Hub-and-Spoke or allergist-integrative models in the future. When comparing outcomes between the Hub (allergist-led) and Spoke (non-allergist-led) Clinics, we identified that the Hub clinic recommended significantly more patients for vaccination. Several factors may have contributed to this difference. Firstly, prior to the establishment of the Hub-and-Spoke model, the existing VAS service at the Hub was already evaluating pre-vaccination patients who were deemed "higher risk". In our previous published experience, 98% of these initial patients were recommended vaccination, and subsequently completed their COVID-19 vaccinations safely 6 . This initial experience likely allowed doctors at the Hub to become familiar and more confident with the safety of COVID-19 vaccines. Secondly, allergists at the Hub clinic may have been less conservative in their recommendations. Patients in Hong Kong with a prior history of suspected "anaphylaxis" or severe, immediate-type allergic reactions to multiple classes of drugs/foods were deemed at possible risk of undiagnosed excipient allergy and cautioned against COVID-19 vaccination prior to allergist evaluation. Despite having allergist support and freedom to redivert patients back to the Hub, non-allergists may have felt less confident in excluding possible excipient allergy and adopted a relatively cautious approach, thus recommending fewer patients for vaccination. However, our follow-up analysis also identified that patients assessed at the Hub (allergist-led) clinic were significantly more likely to get vaccinated than patients assessed in Spoke Clinics by nonallergists. This is likely a result not only in more effective risk stratification, but suggests the role of other contributing factors from both patients and doctors. It is known that healthcare provider recommendation is paramount for acceptance of various vaccines 9 . Patients are likely to have a preformed preference for receiving advice from a specialist doctor. The Hong Kong healthcare system lacks gatekeeping for specialist referrals with relative ease of access to most specialist services. This may have conditioned many patients to always seek "specialist opinion" and be accustomed to receiving such assessments readily [10] [11] [12] . In particular, with vaccine allergy perceived as a highly specialized topic, patients may place less trust and confidence in the advice given by non-allergists. These patient preconceptions are perhaps not unfounded. Factors involving the doctor may include the content of advice, but also the manner in which the advice was conveyed. Doctors in the Hub clinic are well-versed with allergy-related counselling in their line of work. During vaccine allergy assessment, it was pertinent to offer reassurance, similar to the support allergists offer in various clinical scenarios, where they are faced with patient anxiety and scepticism. Hub doctors also likely tend to be more comfortable and confident in their own judgment, which can greatly impact patient perception 13, 14 . In addition, specialist clinics were more able to provide guidance regarding conditions unrelated to COVID-19 vaccine allergies. As mentioned, inappropriately referred patients were often concerned over other immunological conditions, such as allergic rhinitis, asthma, atopic dermatitis, food allergies, or chronic spontaneous urticaria. These conditions are often misunderstood to be related to vaccine allergy, or falsely attributed to higher risk of allergy in general [15] [16] [17] [18] . It is likely that the Hub clinic was also able to address these concerns more holistically and provide advice on the management of these conditions where necessary. With better control of various immunological conditions, this could have also led to more patient confidence and subsequent vaccinations. The specific factors associated with patient confidence and willingness to receive vaccination following consultation warrants dedicated studies in the future. Limitations of this study include its study design utilizing medical record review and telephone for follow-up interviews. We did not include patients who did not attend their appointments nor calculate the default rates for each clinic. Data for potential confounders (such as co-existing comorbidities or other drug allergies) and complete COVID-19 vaccination status were not available for patients outside the subgroup analysis (i.e., the six other Spoke Clinics). Further details regarding prior drug allergies could not be analysed. There may also have been possible referral bias; as the Hub was able to provide additional Immunology & Allergy services, it therefore saw a disproportionately higher number of patients referred for "other" allergy indications (such as prior suspected excipient allergies, idiopathic anaphylaxis). However, we would anticipate that this would have lowered the Hub recommendation rate. Additionally, the vaccination rates presented represent only a snapshot of the current vaccination status. Patients who were not vaccinated at the time of data collection (for example waiting for their vaccine appointments) may have subsequently received vaccination. In conclusion, vaccine hesitancy is complex and multifaceted, with factors involving healthcare providers, patients, media, social environment, and healthcare and political systems. This study has illustrated the crucial role of allergy specialists in reaffirming vaccine safety and countering vaccine hesitancy. Scarcity in allergists in Hong Kong is no new predicament 7 . Although this pandemic allowed for opportunities for collaboration with other specialties and allied health services, it shows a critical need for further development and resources in this area of healthcare in Hong Kong. The Hub-and-Spoke model has proven to be successful for the vaccination campaign, and we are hopeful that it can be similarly adapted for other valuable services as allergists across the territory remain scarce. As a result of this pilot, a population-wide active Penicillin Allergy Delabeling Initiative is also being developed using the same model. Results from the study showed considerable differences in outcomes between allergist-led and non-allergist clinics. Precise reasons for these differences warrant further examination, in order to develop more effective strategies to tackle future population-wide campaigns and programs. 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