title: Measles outbreak in South Africa: epidemiology of laboratory-confirmed measles cases and assessment of intervention, 2009-2011.
abstract: BACKGROUND
  Since 1995, measles vaccination at nine and 18 months has been routine in South Africa; however, coverage seldom reached >95%. We describe the epidemiology of laboratory-confirmed measles case-patients and assess the impact of the nationwide mass vaccination campaign during the 2009 to 2011 measles outbreak in South Africa.
  
  
  METHODS
  Serum specimens collected from patients with suspected-measles were tested for measles-specific IgM antibodies using an enzyme-linked immunosorbent assay and genotypes of a subset were determined. To estimate the impact of the nationwide mass vaccination campaign, we compared incidence in the seven months pre- (1 September 2009-11 April 2010) and seven months post-vaccination campaign (24 May 2010-31 December 2010) periods in seven provinces of South Africa.
  
  
  RESULTS
  A total of 18,431 laboratory-confirmed measles case-patients were reported from all nine provinces of South Africa (cumulative incidence 37 per 100,000 population). The highest cumulative incidence per 100,000 population was in children aged <1 year (603), distributed as follows: <6 months (302/100,000), 6 to 8 months (1083/100,000) and 9 to 11 months (724/100,000). Forty eight percent of case-patients were ≥ 5 years (cumulative incidence 54/100,000). Cumulative incidence decreased with increasing age to 2/100,000 in persons ≥ 40 years. A single strain of measles virus (genotype B3) circulated throughout the outbreak. Prior to the vaccination campaign, cumulative incidence in the targeted vs. non-targeted age group was 5.9-fold higher, decreasing to 1.7 fold following the campaign (P<0.001) and an estimated 1,380 laboratory-confirmed measles case-patients were prevented.
  
  
  CONCLUSIONS
  We observed a reduction in measles incidence following the nationwide mass vaccination campaign even though it was conducted approximately one year after the outbreak started. A booster dose at school entry may be of value given the high incidence in persons >5 years.
authors: Centre for Vaccines and Immunology, National Institute for Communicable Diseases (NICD) of the National Health Laboratory Service (NHLS), Johannesburg, South Africa. genevien@nicd.ac.za
authors: Genevie M
authors: GM
authors: Ntshoe
authors: Johanna M
authors: JM
authors: McAnerney
authors: Brett N
authors: BN
authors: Archer
authors: Sheilagh B
authors: SB
authors: Smit
authors: Bernice N
authors: BN
authors: Harris
authors: Stefano
authors: S
authors: Tempia
authors: Mirriam
authors: M
authors: Mashele
authors: Beverley
authors: B
authors: Singh
authors: Juno
authors: J
authors: Thomas
authors: Ayanda
authors: A
authors: Cengimbo
authors: Lucille H
authors: LH
authors: Blumberg
authors: Adrian
authors: A
authors: Puren
authors: Jocelyn
authors: J
authors: Moyes
authors: Johann
authors: J
authors: van den Heever
authors: Barry D
authors: BD
authors: Schoub
authors: Cheryl
authors: C
authors: Cohen
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D019411:Clinical Laboratory Techniques; D004196:Disease Outbreaks / Q000517:prevention & control*; D005260:Female; D005838:Genotype; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D015994:Incidence; D007223:Infant; D008297:Male; D008457:Measles / Q000453:epidemiology* / Q000235:genetics / Q000276:immunology / Q000517:prevention & control*; D008458:Measles Vaccine / Q000008:administration & dosage / Q000276:immunology; D015203:Reproducibility of Results; D013019:South Africa / Q000453:epidemiology; D014611:Vaccination
chemical_list: D007075:Immunoglobulin M; D008458:Measles Vaccine