Investigation of Risk Factors for Immunization Stress-Related Response to COVID-19 Vaccination and the Importance of History of Allergy as a Newly Identified Risk Factor

Background: This study aimed to evaluate adverse reactions to vaccination using a web-based questionnaire and examine the risk factors for the occurrence of immunization stress-related response (ISRR). Methods: We conducted a questionnaire survey using Google Form® among employees of St. Marianna University Hospital who had received the COVID-19 vaccine between April 2021 and May 2021, 1 week after the first and second vaccinations. We developed and used a questionnaire to identify people with ISRR, according to the WHO diagnostic criteria. A generalized linear mixed model was constructed with ISSR onset as the dependent variable, subjects as the random factor, and each parameter as a fixed factor. A multivariate model was constructed using the forced imputation method with factors that were significant in the univariate analysis. Findings: The number of respondents to the first and second questionnaires were 2,073 and 1,856, respectively. There were 55 and 33 ISRR cases with the first and second vaccinations, respectively. Univariate analysis showed that strong pre-vaccination anxiety (OR, 2·3; 95% CI, 1·30–4·12, p = 0·004) and history of allergy (OR, 1·6; 95% CI, 1·14–2·24, p = 0·007) were significant risk factors. Multivariate analysis also showed that strong pre-vaccination anxiety (OR, 2·1; 95% CI, 1·15–3·80, p = 0·016) and history of allergy (OR, 1·5; 95% CI, 1·09–2·15, p = 0·014) were significant risk factors. Interpretation: Confirmation of allergy prior to vaccination and subsequent action are important for addressing ISRR. Funding: None to declare. Declaration of Interest: None to declare. Ethical Approval: This study was approved by the St. Marianna University School of Medicine Ethics Committee (Approval number: 5261).