The effect of immunization on measles incidence in the Democratic Republic of Congo
Methods: We used available data from the 2010-2013 IDSR system for measles suspected cases counts reported weekly by health zone to investigate the decline in measles incidence post-immunization (by health zone) with one dose of measles containing vaccine (MCV1) with and without the addition of Supplementary Immunization Activities (SIAs). The impact of measles immunization by health zone was modeled with poisson regression, using vaccination coverage levels from two years prior.
Results: At the provincial level, median incidence ranged from 0.67 to 7.67 per 100,000 in 2010, while the median incidence ranged from 0.96 to 273.8 per 100,000 in 2012. In 2013, median incidence ranged from 5.79 to 322.61 per 100,000. Furthermore, multivariate modeling at the health zone level showed that each 1% increase in MCV1 coverage was associated with a .79% decrease in incidence. The addition of an SIA in a health zone was associated with a 2.34% increase in incidence.
Conclusion: Our results highlight the fact that measles in DRC is highly susceptible to immunization programs, particularly mass campaigns. Repeated occurrences of large-scale outbreaks in DRC suggest that vaccination coverage rates are grossly overestimated and signify the importance of the re-evaluation of measles virus dynamics and prevention and control strategies.
N. Hoff, None
J. J. Muyembe, None
E. Okitolonda, None
A. Rimoin, None