title: A long-lasting measles epidemic in Maroua, Cameroon 2008-2009: mass vaccination as response to the epidemic.
abstract: BACKGROUND
  A measles outbreak occurred in Maroua, Cameroon, from January 2008 to April 2009. In accordance with recent World Health Organization guidelines, an outbreak-response immunization (ORI) was conducted in January 2009. The aim of this study was to investigate the causes of the epidemic in order to guide vaccination strategies.
  
  
  METHODS
  We performed a stratified household-based survey using cluster sampling to determine measles vaccination coverage in children aged 9 months to 15 years. We defined 3 strata based on measles incidence. Next, we performed a case-control study to measure vaccine effectiveness (VE). Cases were obtained from health center registries. Controls were selected among respondents to the coverage survey.
  
  
  RESULTS
  The vaccination-coverage survey included 2963 children in total. The overall routine vaccination coverage was 74.1% (95% confidence interval [CI]: 70.0%-78.3%). Measles incidence was inversely proportional to routine vaccination coverage, with high incidence associated with coverage of 71% and low incidence associated with coverage of 84%. The overall VE was 94% (95% CI, 86.7%-97.4%). After the ORI in January 2009, the coverage was >90% in all strata and measles incidence declined rapidly.
  
  
  CONCLUSIONS
  Our results confirm that insufficient vaccination coverage was the main reason for this epidemic. The ORI conducted in January 2009 contributed both to control the epidemic and to increase the vaccination coverage to desirable levels.
authors.affiliation: Epicentre, Paris, France. fluquero@epicentre.msf.org
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Luquero
authors.forename: Heloise
authors.initials: H
authors.lastname: Pham-Orsetti
authors.forename: D A T
authors.initials: DA
authors.lastname: Cummings
authors.forename: Philippe E
authors.initials: PE
authors.lastname: Ngaunji
authors.forename: Marcelino
authors.initials: M
authors.lastname: Nimpa
authors.forename: Florence
authors.initials: F
authors.lastname: Fermon
authors.forename: Ndong
authors.initials: N
authors.lastname: Ngoe
authors.forename: Stephen
authors.initials: S
authors.lastname: Sosler
authors.forename: Peter
authors.initials: P
authors.lastname: Strebel
authors.forename: Rebecca F
authors.initials: RF
authors.lastname: Grais
mesh_terms: D000293:Adolescent; D002163:Cameroon / Q000453:epidemiology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D058872:Epidemics / Q000517:prevention & control; D005260:Female; D006306:Health Surveys; D006801:Humans; D017589:Immunization Programs; D015994:Incidence; D007223:Infant; D008297:Male; D032541:Mass Vaccination / Q000592:standards; D008457:Measles / Q000453:epidemiology* / Q000517:prevention & control; D008458:Measles Vaccine / Q000008:administration & dosage* / Q000592:standards; D011159:Population Surveillance; D013997:Time Factors
chemical_list: D008458:Measles Vaccine