Measles Resurgence Following a Nationwide Measles Vaccination Campaign in Nigeria, 2005-2008

Introduction. From 1990 through 2008, routine immunization coverage of measles vaccine in Nigeria ranged from 35% to 70%. Nigeria conducted a nationwide measles vaccination campaign in 2 phases during 2005-2006 that targeted children aged 9 months to 14 years; in 2008, a nationwide follow-up campaign that targeted children aged 9 months to 4 years was conducted in 2 phases. Despite these efforts, measles cases continued to occur. Methods. This is a descriptive study that reviewed the measles immunization coverage data from administrative, World Health Organization, United Nations Children's Fund, survey, and supplemental immunization activities data. Measles surveillance data were analyzed from case-based surveillance reports. Results. Confirmed measles cases increased from 383 in 2006 to 2542 in 2007 and to 9510 in 2008. Of the confirmed cases in 2008, 717 (30%) occurred in children <2 years of age, 1145 (48%) in children 2-4 years of age, and 354 (14%) were in children 5-14 years of age. In 2008, the measles case fatality rate was 1.2%. Conclusions. Suboptimal routine coverage and the wide interval between the catch-up and follow-up campaigns likely led to an accumulation of children susceptible to measles.