Development of a COVID-19 Vaccination Anxiety Scale to measure COVID-19 vaccine anxiety in Japanese adults

Since 2020, COVID-19 vaccines have been rapidly developed and distributed free of charge in several countries, but there remains deep-seated distrust and anxiety regarding their efficacy and safety. This study aimed to develop the C19-VAS to measure COVID-19 vaccine anxiety in Japanese adults. 500 Japanese participants were recruited through the web survey service. To assess test-retest reliability, the same participants were surveyed again after a four-week interval. These participants responded to the C19-VAS, the Japanese version of the Fear of COVID-19 Scale (FCV-19S), the Japanese version of the 7C of Vaccination Readiness (7C), the Japanese version of the Generic Conspiracist Beliefs Scale (GCBS-J), the Japanese versions of the Perceived Vulnerability to Disease (PVD-J), and socio-demographic variables. Results indicated the factor structure of the C19-VAS as including 25 items and 3 factors: "Anxiety Related to Vaccine Confidence ( = .96, {omega} = .96)," "Emotional Symptoms of Anxiety ( = .91, {omega} = .91)," and "Anxiety about Infection after Vaccination ( = .76, {omega} = .78)." The confirmatory factor analysis findings supported the 3 factors structure of the C19-VAS across gender with good fit statistics: CFI = .868, RMSEA = .071, SRMR = .079, AIC = 1434.177. The scale showed adequate construct validity, as indicated by significantly correlations with the FCV-19S-J (r = .44), 7C (r = -.59), GCBS-J (r = .55) and PVD-J (r = .19). Additionally, the ICC between Time 1 and Time 2 for "Anxiety Related to Vaccine Confidence" was .94, "Emotional Symptoms of Anxiety" was .91, and "Anxiety about Infection after Vaccination" was .81. This study clarified the factor structure of the C19-VAS and demonstrated its good internal consistency and test-retest reliability.