title: Progress towards measles elimination in Singapore.
abstract: OBJECTIVE
  We describe the epidemiological trends of measles in Singapore in relation to its progress towards measles elimination and identify gaps in fulfilling the World Health Organization Western Pacific Regional Office regional measles elimination criteria.
  
  
  METHODS
  Epidemiological data on measles maintained by the Communicable Diseases Division, Ministry of Health from 1981 to 2012 were collated and analysed. Data on measles vaccination coverage were obtained from the National Immunization Registry and School Health Services, Health Promotion Board. To assess the seroprevalence of the population, the findings of periodic seroepidemiological surveys on measles were traced and reviewed.
  
  
  RESULTS
  With the successful implementation of the National Childhood Immunization Programme using the monovalent measles vaccine, measles incidence declined from 88.5 cases per 100,000 in 1984 to 6.9 per 100,000 in 1991. Resurgences were observed in 1992, 1993 and 1997. A 'catch-up' vaccination programme using the trivalent measles, mumps and rubella (MMR) vaccine was conducted in 1997, followed by introduction of the two-dose vaccination schedule in January 1998. Measles incidence subsequently declined sharply to 2.9 per 100,000 in 1998. Vaccination coverage was maintained at 95% for the first dose and 92-94% for the second dose. Seroprevalence surveys showed seropositivity for measles IgG antibodies in over 95% of adults in 2004, and in 83.1% of children aged 1-17 years in 2008-2010. Sporadic cases with occasional clusters of two or more cases continued to occur among the unvaccinated population, especially children aged below 4 years. The predominant measles virus genotype has shifted from D9 to the B3 and G3 genotypes, which are endemic in neighbouring countries.
  
  
  CONCLUSIONS
  Singapore has made good progress towards the elimination of endemic measles. To further eliminate sporadic cases of measles, the national immunisation schedule has recently been amended to vaccinate children with 2 doses of MMR vaccine before 2 years of age.
authors.affiliation: Department of Clinical Epidemiology, Tan Tock Seng Hospital, Singapore. Electronic address: hanleyho@gmail.com.
authors.forename: Hanley J
authors.initials: HJ
authors.lastname: Ho
authors.affiliation: Public Health Group, Ministry of Health, Singapore.
authors.forename: Constance
authors.initials: C
authors.lastname: Low
authors.affiliation: Public Health Group, Ministry of Health, Singapore.
authors.forename: Li Wei
authors.initials: LW
authors.lastname: Ang
authors.affiliation: Public Health Group, Ministry of Health, Singapore.
authors.forename: Jeffery L
authors.initials: JL
authors.lastname: Cutter
authors.affiliation: Public Health Group, Ministry of Health, Singapore.
authors.forename: Joanne
authors.initials: J
authors.lastname: Tay
authors.affiliation: Department of Pathology, Singapore General Hospital, Singapore.
authors.forename: Kwai Peng
authors.initials: KP
authors.lastname: Chan
authors.affiliation: Public Health Group, Ministry of Health, Singapore.
authors.forename: Peng Lim
authors.initials: PL
authors.lastname: Ooi
authors.affiliation: Department of Paediatric Medicine, KK Women's and Children's Hospital, Singapore; Duke-National University of Singapore Graduate Medical School, Singapore; Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Koh Cheng
authors.initials: KC
authors.lastname: Thoon
authors.affiliation: Public Health Group, Ministry of Health, Singapore; Saw Swee Hock School of Public Health, National University of Singapore, Singapore.
authors.forename: Kee Tai
authors.initials: KT
authors.lastname: Goh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000914:Antibodies, Viral / Q000097:blood; D002648:Child; D002675:Child, Preschool; D060740:Disease Eradication; D005260:Female; D005838:Genotype; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D008297:Male; D008457:Measles / Q000453:epidemiology* / Q000276:immunology*; D008458:Measles Vaccine / Q000008:administration & dosage; D008459:Measles virus / Q000145:classification / Q000235:genetics; D008875:Middle Aged; D016036:Seroepidemiologic Studies; D012846:Singapore / Q000453:epidemiology; D014611:Vaccination / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G; D008458:Measles Vaccine
keywords: Genotypes; Immunisation; Measles; Seroepidemiology; Singapore; Surveillance