title: Mass vaccination with a two-dose oral cholera vaccine in a long-standing refugee camp, Thailand.
abstract: BACKGROUND
  During 2005-2012, surveillance in Maela refugee camp, Thailand, identified four cholera outbreaks, with rates up to 10.7 cases per 1000 refugees. In 2013, the Thailand Ministry of Public Health sponsored a two-dose oral cholera vaccine (OCV) campaign for the approximately 46,000 refugees living in Maela.
  
  
  METHODS
  We enumerated the target population (refugees living in Maela who are ≥1 year old and not pregnant) in a census three months before the campaign and issued barcoded OCV cards to each individual. We conducted the campaign using a fixed-post strategy during two eight-day rounds plus one two-day round for persons who had missed their second dose and recorded vaccine status for each individual. To identify factors associated with no vaccination (versus at least one dose) and those associated with adverse events following immunization (AEFI), we used separate marginal log-binomial regression models with robust variance estimates to account for household clustering.
  
  
  RESULTS
  A total of 63,057 OCV doses were administered to a target population of 43,485 refugees. An estimated 35,399 (81%) refugees received at least one dose and 27,658 (64%) received two doses. A total of 993 additional doses (1.5%) were wasted including 297 that were spat out. Only 0.05% of refugees, mostly children, could not be vaccinated due to repeated spitting. Characteristics associated with no vaccination (versus at least one dose) included age ≥15 years (versus 1-14 years), Karen ethnicity (versus any other ethnicity) and, only among adults 15-64 years old, male sex. Passive surveillance identified 84 refugees who experienced 108 AEFI including three serious but coincidental events. The most frequent AEFI were nausea (49%), dizziness (38%), and fever (30%). Overall, AEFI were more prevalent among young children and older adults.
  
  
  CONCLUSIONS
  Our results suggest that mass vaccination in refugee camps with a two-dose OCV is readily achievable and AEFI are few.
authors.affiliation: Division of Global Migration and Quarantine, Centers for Disease Control and Prevention, 1600 Clifton Rd NE, Mailstop E03, Atlanta, GA 30329, USA; Thailand Ministry of Public Health, U.S. Centers for Disease Control and Prevention Collaboration, Ministry of Public Health, Tivanond Road, Nonthaburi 11000, Thailand. Electronic address: cphares@cdc.gov.
authors.forename: Christina R
authors.initials: CR
authors.lastname: Phares
authors.affiliation: Global Immunization Division, Centers for Disease Control and Prevention, 1600 Clifton Rd NE, Mailstop A04, Atlanta, GA 30329, USA. Electronic address: kdate@cdc.gov.
authors.forename: Kashmira
authors.initials: K
authors.lastname: Date
authors.affiliation: Première Urgence-Aide Médicale Internationale, 21/22-26 Mae Sot-Mae Tao road Tak 63110, Thailand. Electronic address: travers_philippe@yahoo.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Travers
authors.affiliation: Première Urgence-Aide Médicale Internationale, Paris, France. Electronic address: cdeglise@pu-ami.org.
authors.forename: Carole
authors.initials: C
authors.lastname: Déglise
authors.affiliation: Thailand Ministry of Public Health, U.S. Centers for Disease Control and Prevention Collaboration, Ministry of Public Health, Tivanond Road, Nonthaburi 11000, Thailand. Electronic address: nwongjindanon@cdc.gov.
authors.forename: Nuttapong
authors.initials: N
authors.lastname: Wongjindanon
authors.affiliation: Division of Global Migration and Quarantine, Centers for Disease Control and Prevention, 1600 Clifton Rd NE, Mailstop E03, Atlanta, GA 30329, USA; Thailand Ministry of Public Health, U.S. Centers for Disease Control and Prevention Collaboration, Ministry of Public Health, Tivanond Road, Nonthaburi 11000, Thailand. Electronic address: ortegal@cdc.gov.
authors.forename: Luis
authors.initials: L
authors.lastname: Ortega
authors.affiliation: Department of Disease Control, Thailand Ministry of Public Health, Tivanond Road, Nonthaburi 11000, Thailand. Electronic address: tapanokr@yahoo.com.
authors.forename: Ponchanok Rattanadilok Na
authors.initials: PR
authors.lastname: Bhuket
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D002771:Cholera / Q000453:epidemiology / Q000517:prevention & control*; D022121:Cholera Vaccines / Q000008:administration & dosage* / Q000009:adverse effects; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology / Q000473:pathology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D032541:Mass Vaccination / Q000379:methods*; D008875:Middle Aged; D012036:Refugees; D013785:Thailand / Q000453:epidemiology; D055815:Young Adult
chemical_list: D022121:Cholera Vaccines
keywords: Cholera; Epidemiology; Oral cholera vaccines; Refugees; Thailand