Impact of an accelerated measles-mumps-rubella (MMR) vaccine schedule on vaccine coverage: An ecological study among London children, 2012-2018.

BACKGROUND

Vaccination coverage of dose two of MMR (MMR2) at 5th birthday has been consistently low in London and measured 76.3% in 2018/19. Since the early 2000s seven boroughs in London started offering dose two earlier, from 15 to 18 months onwards instead of the recommended 3 years 4 months. In this study we investigate whether the accelerated schedule of MMR2 leads to a change in coverage of MMR2 and other childhood vaccines with an ecological study using childhood immunisation data from 2009 to 2018 in London.

METHODS

We modelled coverage used generalized estimating equations (GEE) adjusted for year and DTaP/IPV/Hib3 coverage measured at 2nd birthday as a proxy for baseline local vaccination programme performance to determine the percentage point difference in coverage of MMR2 and other childhood vaccines.

RESULTS

Average MMR2 coverage was higher among early implementing boroughs from 2012/13 onwards. Coverage difference was highest in 2017/18 (9.2 percentage points, 95% CI 4.8, 13.5, p < 0.001). On average over the 6 years, compared to London boroughs on the routine schedule, MMR2 coverage among early implementing boroughs was 3.3 percentage points higher (95% CI 1.3, 5.3, p = 0.01) after adjusting for DTaP/IPV/Hib3 coverage, IMD score and year.

CONCLUSION

Earlier vaccination of MMR2 is associated with significantly higher coverage at five years for this vaccine in London. Further research is needed to assess the association at a more granular level, but our findings underline a potential opportunity to increase MMR coverage.