(330) A population-based observational study of determinants of varicella vaccination in the private market in Denmark

Background: Varicella is one of the most contagious diseases affecting approximately 90% of children before the age of ten, and thus constitutes a considerable health and societal burden. Currently, varicella vaccination is not part of the Danish National Immunization Program (NIP) but has been available for out-of-pocket purchase since 2019. No data are available on patterns in varicella vaccination uptake in Denmark.

Objectives: To determine private market uptake of varicella vaccination in Denmark from 2019 to 2022 and to examine potential sociodemographic differences.

Methods: This nationwide, population-based study was based on 1,320,408 individuals aged 1 to 18 years. Data on sociodemographic factors for children and their parents were obtained from Statistics Denmark’s registers and linked to varicella vaccination status in the Danish Vaccination Register. Associations were estimated by crude and adjusted multivariable logistic regression models. We accounted for time trend as for the dependency between siblings by applying a robust standard error estimator.


Results: Varicella vaccination coverage rates increased five-fold from 2019 to 2022, with the highest uptake in the youngest age-groups ( <10 years). The likelihood of vaccination was markedly increased among children of parents with high education (aOR: 5.99, 95% CI: 4.50-7.98), high income (aOR: 3.06, 95% CI: 2.77-3.38), and education within medicine or nursing specifically (aOR: 1.87, 95% CI: 1.77-1.99). Further, varicella vaccination was most common among children living in capital region of Denmark and in the metropolitan municipalities.

Conclusion: Varicella vaccination uptake is greater among children of families with high socioeconomic status and those living in capital/metropolitan areas. It is conceivable that the observed social inequality will persist, or even increase, over time as varicella vaccine uptake may increase. To ensure equitable access to varicella vaccination and to prevent disease among children, the value of including varicella vaccine in NIP should be evaluated.