title: Effectiveness of Rubella vaccine in a rubella outbreak in Guangzhou city, China, 2014.
abstract: BACKGROUND
  WHO recommends the use of rubella-containing vaccine (RCVs) to prevent rubella and congenital rubella syndrome (CRS). Most licensed rubella vaccines in use globally are based on RA27/3 strains and have estimated vaccine effectiveness (VE) rates of 95-100%. In contrast, China uses a BRD-II strain-based rubella vaccine. Few field studies have been conducted that estimate VE of China's RCV. On March 17, 2014, a rubella outbreak was reported in a middle school in Guangzhou city, China. We conducted an investigation to understand reasons for the outbreak, and we used that investigation to estimate vaccine effectiveness of China's rubella vaccine.
  
  
  METHODS
  To identify cases, investigators reviewed records kept by the school doctor and absentee records kept by teachers. Self-administered questionnaires were sent to parents of all students to collect information about the students' symptoms, the results of any physician consultation, and disease history. We obtained demographic information and illness information for all students in the school; vaccination status was determined by inspection of official, parent-held vaccination records. A retrospective cohort study was conducted in 13 classes that had secondary cases of rubella. Using the secondary attack rates, we evaluated VE by the number of RCV doses received and age at vaccination.
  
  
  RESULTS
  During the period February 17-May 23, 2014, 162 students (50 suspected cases, 88 probable cases, 24 confirmed cases) were diagnosed with rubella, yielding an overall attack rate of 10% (162/1621). Cases occurred in 27 classes (73%) of 37 classrooms. Secondary cases occurred in 13 classes (35%) of 37 classrooms. A total of 1130 students (69.7%) have vaccination certificates; 419 (37%) students were record-confirmed to have received RCV. For those vaccinated using BRD-II strain vaccine, vaccine effectiveness (VE) was 94% (95%CI: 75-98). VE for measles, mumps, and rubella (MMR) vaccine which is based on either BRD-II or RA27/3 strain was 89% (95%CI: 56-97). VE of a single dose of domestic monovalent rubella vaccine that used BRD-II strain vaccine was 93% (95%CI: 73-98). VE for those who received the vaccine between 1 and 2 years of age was 95% (95% CI: 67-99) while the VE was 100% for those vaccinated after 2 years of age. VE among those who received RCV <12 years ago was 100% while VE among those who received RCV ≥12 years ago was 92% (95%CI: 70-98).
  
  
  CONCLUSIONS
  The rubella vaccines used in China that are based on the BRD-II rubella vaccine strain have VE of 94%, which is similar to the more commonly used RA27/3-based RCVs. Low vaccination coverage contributed to this outbreak; early reporting of an outbreak is necessary for effective outbreak response immunization.
authors.affiliation: Jinan Center for Disease Control and Prevention, Jinan 250021, Shandong, China; Chinese Field Epidemiology Training Program (CFETP), Chinese Center for Disease Control and Prevention, Beijing 100050, China.
authors.forename: Caiyun
authors.initials: C
authors.lastname: Chang
authors.affiliation: Dongguan Center for Disease Control and Prevention, Dongguan 523000, Guangdong, China; Guangdong Field Epidemiology Training Program (GDFETP), Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, Guangdong, China.
authors.forename: Xianghuan
authors.initials: X
authors.lastname: Mo
authors.affiliation: Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, Guangdong, China.
authors.forename: Pei
authors.initials: P
authors.lastname: Hu
authors.affiliation: Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, Guangdong, China.
authors.forename: Wenjia
authors.initials: W
authors.lastname: Liang
authors.affiliation: Chinese Field Epidemiology Training Program (CFETP), Chinese Center for Disease Control and Prevention, Beijing 100050, China.
authors.forename: Huilai
authors.initials: H
authors.lastname: Ma
authors.affiliation: National Center of Immunization Program, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
authors.forename: Zhijie
authors.initials: Z
authors.lastname: An
authors.affiliation: Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, Guangdong, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.affiliation: Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, Guangdong, China. Electronic address: zhzgdcdc@163.com.
authors.forename: Huizhen
authors.initials: H
authors.lastname: Zheng
mesh_terms: D000293:Adolescent; D000328:Adult; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D004196:Disease Outbreaks / Q000517:prevention & control; D005260:Female; D055991:Health Records, Personal; D006801:Humans; D008457:Measles / Q000517:prevention & control; D022542:Measles-Mumps-Rubella Vaccine / Q000008:administration & dosage / Q000276:immunology*; D009107:Mumps / Q000517:prevention & control; D010290:Parents; D012189:Retrospective Studies; D012409:Rubella / Q000453:epidemiology* / Q000517:prevention & control*; D012410:Rubella Syndrome, Congenital / Q000517:prevention & control; D012574:Schools; D011795:Surveys and Questionnaires; D014611:Vaccination; D064166:Vaccine Potency
chemical_list: D022542:Measles-Mumps-Rubella Vaccine
keywords: Outbreak; Rubella; Secondary attack rate; Vaccine effectiveness