Vaccine hesitancy and reported non-vaccination in an Irish pediatric outpatient population

Vaccine hesitancy is defined as a delay in acceptance, or refusal, of vaccines, despite availability. It is a complex and context specific phenomenon and identified as a global health priority. The "Parent Attitudes about Childhood Vaccines" (PACV) questionnaire is a validated tool for identifying vaccine hesitancy. Our aim was to use the PACV to assess vaccine hesitancy and its relationship with reported non-vaccination in an Irish population, for the first time. Our participants were parents or caregivers of children attending general pediatric clinics in a tertiary pediatric hospital in Dublin, Ireland, between September and December 2018. In total, 436 participants completed the questionnaire. 5.5% of our population reported non-vaccination. Human papilloma virus and measles, mumps, rubella vaccines were the most commonly cited vaccines of concern (11.5% and 6.7%, respectively), and autism spectrum disorder was the most commonly side effect of concern (4.3%). Mean PACV score was 26.9 (SD 19.1), with a significant difference between non-vaccinators and vaccinators (53.2 vs 25.3, p<0.001). Safety and efficacy concerns were the major contributor to non-vaccination. 14.4% of our population were vaccine-hesitant using the conventional cut-off score, which increased to 22% when using an optimal cut-off which maximized sensitivity and specificity. The accuracy of the PACV score to identify non-vaccination was good (area under the ROC curve = 0.827), and the optimal cut-off had a high negative predictive value (98.5%).Conclusion: PACV identified reported non-vaccination with high accuracy in our population. It may be useful to screen vaccine-hesitant parents who could benefit from interventions to improve uptake. What is Known: • Vaccine hesitancy is a leading threat to global health, with falls in vaccine uptake associated with disease outbreaks worldwide. • The Parent Attitudes about Childhood Vaccines (PACV) questionnaire is a validated measure of vaccine hesitancy and correlates with non-vaccination in many populations. What is New: • This large study in a pediatric outpatient clinic setting represents the first use of the PACV in a Western European population to assess vaccination hesitancy. • The PACV may be an effective way of screening a pediatric clinic population to identify vaccine-hesitant parents or caregivers for targeted vaccine promotion.