Impact of inclusion of rubella attenuated live vaccine into National Expanded Program for Immunization on rubella incidence in Liaoning province: an interrupted time series analysis

  Objective  To assess the impact of rubella attenuated live vaccine (RV) administration on the trend of rubella incidence after the inclusion of RV into National Expanded Program for Immunization (NEPI).

  Methods  We extracted data on rubella incidence rates from 2004 through 2016 in Liaoning province and then explore the trend of incidence before and after the RV administration using interrupted time series analysis and segmented regression model.

  Results  Before the inclusion of RV into NEPI, the average monthly rubella incidence was 1.22 per 100 000 population and the incidence rate showed a significant ascending trend with an increment of 0.018 per 100 000 population per month (P = 0.01). After the inclusion of RV into NEPI, the average monthly rubella incidence was 0.176 2 per 100 000 population, with a significant immediate decrease (β₂ = 1.702 9, P = 0.006 8). Although, there was a 0.024 1 decrease in the slope of monthly rubella incidence ( – 0.006 1) after the inclusion of RV into the NEPI, but the slope did not differ significantly compared to that before the inclusion (P = 0.124).

  Conclusion  The inclusion of RV into the National Expanded Program for Immunization has decreased rubella incidence but its long-term effect needs to be observed in Liaoning province.