Multiple-component interventions to increase rotavirus vaccine uptake in children: a randomised controlled trial

Rotavirus vaccine has not been included in the Hong Kong Government's Childhood Immunisation Programme. This randomised controlled trial examined whether a simple intervention package can increase rotavirus vaccine uptake in Hong Kong children.

Postpartum mothers were recruited from two public hospitals in Hong Kong and randomly allocated into three groups using block randomisation, with block sizes kept unknown to investigators and research staff. Control-subjects received public rotavirus information. Subjects in intervention group 1 additionally received: key rotavirus information with a hyperlink to a webpage showing private clinics providing rotavirus vaccines and guidance on searching the clinics, and vaccination reminders. Subjects in intervention group 2 received the same intervention as group 1, plus tokens to receive free rotavirus vaccines at specific health centres. Rotavirus vaccination status was collected when children were approximately 8 months old. Maternal attitudes towards rotavirus vaccine were assessed at enrolment and at the end of the study. This trial has been registered in the Chinese Clinical Trial Register (Ref.:ChiCTR2000039791).

From 16 February to 30 July 2021, 788 eligible mothers were recruited and randomly allocated to control group (n = 263), intervention group 1 (n = 263), and intervention group 2 (n = 262). The full intervention package (intervention group 2 relative to control group) increased rotavirus vaccine uptake by 1.7 times (95% confidence interval [CI] = 1.49-1.97) or by 33 percent-points (from 48% to 81% uptake). Provision of key rotavirus information with vaccination reminders (intervention group 1 relative to control group) and removal of financial barrier (intervention group 2 relative to intervention group 1) increased uptake by 1.17 times (95% CI = 0.99-1.38) or 8 percent-points, and by 1.46 times (95% CI = 1.29-1.66) or 25 percent-points, respectively.

A multiple-component intervention package, and in particular providing free vaccine, could increase the uptake of rotavirus vaccine in Hong Kong children. The impact of the intervention package was greatest in low-income families, emphasising the importance of removing financial barriers to vaccination to promote equity. Incorporating rotavirus vaccine into the routine CIP could further protect more young children from rotavirus infection and improve equity.

This work was supported by the Health and Medical Research Fund by the Health Bureau, Government of Hong Kong SAR [Ref.: 19180202].