Potential impact of rotavirus vaccine introduction in India’s Universal Immunisation Programme on private sector vaccine utilisation: an interrupted time series analysis

Abstract

Background: Despite free immunisation services through the Universal Immunisation Programme (UIP), around 14% of Indian households seek immunisation in the private sector. We examined the potential impact of rotavirus vaccine (RVV) introduction in the Universal Immunisation Programme (UIP) on private-sector rotavirus vaccine utilisation. Methods: We analysed nationally representative private-sector vaccine sales data. The intervention under consideration is RVV introduction in the UIP in selected Indian states. The outcome is the ‘monthly RVV sales volume’—a proxy for vaccine utilisation. We performed a Poisson regression interrupted time series analysis to detect the pre-intervention trend, post-intervention level change and trend change relative to the pre-intervention for monthly rotavirus vaccine utilisation. Results: Poisson segmented regression analysis showed that immediately after RVV introduction in the UIP private-sector RVV sales showed a decline in Rajasthan by 37.4% (Incidence Risk Ratio (IRR): 0.626; 95% CI: 0.504–0.779), in Tamil Nadu by 26% (IRR: 0.740; 95% CI: 0.513–1.068), in Uttar Pradesh-East by 72.2% (IRR: 0.278; 95% CI: 0.178–0.436) and in Kerala by 3% (IRR: 0.970; 95% CI: 0.651–1.447). Rajasthan, Tamil Nadu and Kerala had sustained reduction in the postintervention trend relative to the preintervention trend by 20.1% (IRR: 0.799; 95% CI: 0.763–0.836), 6.4% (IRR: 0.936; 95% CI: 0.906–0.967) and 3.3% (IRR: 0.967; 95% CI: 0.926–0.960) per month, respectively. However, in Haryana and UP-west, in the first-month post-UIP introduction, the private-sector RVV sales increased by 101% and 3.8%, respectively which was followed by a sustained decrease of 14.2% (IRR: 0.858; 95% CI: 0.688–1.070) and 5.8% (IRR: 0.942; 95% CI: 0.926–0.960) per month, respectively. In terms of long-term impact, the private sector RVV sales post-UIP introduction decreased at a monthly rate of 4.4% (IRR: 0.956, 95% CI: 0.939–0.974) in Rajasthan but increased by 5.5% (IRR: 1.055; 95% CI: 1.040–1.070) in UP-east, 0.3% (IRR: 1.003, 95% CI: 0.976–1.031)) in Kerala and 0.2% (IRR: 1.002, 95% CI: 0.993–1.011) in Tamil Nadu whereas Haryana and UP-west had a reduction in RVV utilisation by 2.8% (IRR: 0.972; 95% CI: 0.955–0.990) and 1% (IRR: 0.990; 95% CI: 0.982–0.998), respectively. Conclusions: The study provides evidence that access to RVV through UIP leads to a reduction in private-sector RVV utilisation. We recommend strengthening UIP to expand the basket of new vaccines.