title: Investigation of a Measles Outbreak in China to Identify Gaps in Vaccination Coverage, Routes of Transmission, and Interventions.
abstract: BACKGROUND
  A measles outbreak occurred in a western county of China in 2013, the year after China's historic nadir of measles. We conducted a field investigation to identify gaps in measles vaccination coverage and immunization program weaknesses, and to provide recommendations for measles outbreak response and immunization program improvement.
  
  
  METHODS
  We analyzed surveillance data from 2008 to 2013 to describe the measles epidemiology of the county. Measles-containing vaccine coverage was estimated using two methods: previously-reported administrative coverage and an estimation of coverage by clinic-kept vaccination records (n = 542). We conducted a rapid field coverage assessment in a migrant population village to evaluate coverage after emergency vaccination. We conducted a review of hospital records of measles cases to address the role hospital transmission played during the early stage of this outbreak.
  
  
  RESULTS
  There were 153 cases in the outbreak, primarily among children too young to vaccinate, unvaccinated children less than 3 years old, and adults. Measles-containing vaccine coverage by the field assessment showed that 20% of children aged 8-17 months had zero doses, and 9% of ≥2 years old children had fewer than two doses. The vaccination statuses of all adult cases were either zero doses or unknown. At least 61% of cases had been hospitalized. The proportion of cases who had been hospital-exposed 7 to 21 days prior to rash onset decreased from 52% to 22% after hospitals strengthen their isolation measures.
  
  
  CONCLUSIONS
  This outbreak was a result of measles vaccination coverage gaps among young children and adults, and insufficient hospital isolation of cases. The lower coverage seen in the field estimation compared with reported coverage showed that reported coverage could have been overestimated. Hospitals were sites of transmission in the early stage of the outbreak. A strict hospital isolation policy could decrease spread of measles. Emergency vaccination was associated with stopping measles transmission in low coverage areas.
authors.affiliation: National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing, China; Chinese Field Epidemiology Training Program, Chinese Center for Disease Control and Prevention, Beijing, China; Taizhou Prefecture Center for Disease Control and Prevention, Taizhou Prefecture, Zhejiang Province, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Gansu Provincial Center for Disease Control and Prevention, Lanzhou, Gansu province, China.
authors.forename: Ningjing
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Gansu Provincial Center for Disease Control and Prevention, Lanzhou, Gansu province, China.
authors.forename: Xiaoshu
authors.initials: X
authors.lastname: Zhang
authors.affiliation: National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Lixin
authors.initials: L
authors.lastname: Hao
authors.affiliation: National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Qiru
authors.initials: Q
authors.lastname: Su
authors.affiliation: Longnan Prefecture Center for Disease Control and Prevention, Longnan Prefecture, Gansu Province, China.
authors.forename: Haijun
authors.initials: H
authors.lastname: Wang
authors.affiliation: Wudu County Center for Disease Control and Prevention, Longnan Prefecture, Gansu Province, China.
authors.forename: Kongyan
authors.initials: K
authors.lastname: Meng
authors.affiliation: Gansu Provincial Center for Disease Control and Prevention, Lanzhou, Gansu province, China.
authors.forename: Binglin
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Gansu Provincial Center for Disease Control and Prevention, Lanzhou, Gansu province, China.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Liu
authors.affiliation: National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Huaqing
authors.initials: H
authors.lastname: Wang
authors.affiliation: National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Huiming
authors.initials: H
authors.lastname: Luo
authors.affiliation: National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Gansu Provincial Center for Disease Control and Prevention, Lanzhou, Gansu province, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.affiliation: National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Ma
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002681:China; D004196:Disease Outbreaks; D005260:Female; D049674:History, 21st Century; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008457:Measles / Q000453:epidemiology* / Q000266:history / Q000517:prevention & control / Q000635:transmission; D008458:Measles Vaccine / Q000276:immunology; D011159:Population Surveillance; D012621:Seasons; D014611:Vaccination; D055815:Young Adult
chemical_list: D008458:Measles Vaccine