title: Pregnancy Outcomes after a Mass Vaccination Campaign with an Oral Cholera Vaccine in Guinea: A Retrospective Cohort Study.
abstract: BACKGROUND
  Since 2010, WHO has recommended oral cholera vaccines as an additional strategy for cholera control. During a cholera episode, pregnant women are at high risk of complications, and the risk of fetal death has been reported to be 2-36%. Due to a lack of safety data, pregnant women have been excluded from most cholera vaccination campaigns. In 2012, reactive campaigns using the bivalent killed whole-cell oral cholera vaccine (BivWC), included all people living in the targeted areas aged ≥ 1 year regardless of pregnancy status, were implemented in Guinea. We aimed to determine whether there was a difference in pregnancy outcomes between vaccinated and non-vaccinated pregnant women.
  
  
  RESULTS
  From 11 November to 4 December 2013, we conducted a retrospective cohort study in Boffa prefecture among women who were pregnant in 2012 during or after the vaccination campaign. The primary outcome was pregnancy loss, as reported by the mother, and fetal malformations, after clinical examination. Primary exposure was the intake of the BivWC vaccine (Shanchol) during pregnancy, as determined by a vaccination card or oral history. We compared the risk of pregnancy loss between vaccinated and non-vaccinated women through binomial regression analysis. A total of 2,494 pregnancies were included in the analysis. The crude incidence of pregnancy loss was 3.7% (95%CI 2.7-4.8) for fetuses exposed to BivWC vaccine and 2.6% (0.7-4.5) for non-exposed fetuses. The incidence of malformation was 0.6% (0.1-1.0) and 1.2% (0.0-2.5) in BivWC-exposed and non-exposed fetuses, respectively. In both crude and adjusted analyses, fetal exposure to BivWC was not significantly associated with pregnancy loss (adjusted risk ratio (aRR = 1.09 [95%CI: 0.5-2.25], p = 0.818) or malformations (aRR = 0.50 [95%CI: 0.13-1.91], p = 0.314).
  
  
  CONCLUSIONS
  In this large retrospective cohort study, we found no association between fetal exposure to BivWC and risk of pregnancy loss or malformation. Despite the weaknesses of a retrospective design, we can conclude that if a risk exists, it is very low. Additional prospective studies are warranted to add to the evidence base on OCV use during pregnancy. Pregnant women are particularly vulnerable during cholera episodes and should be included in vaccination campaigns when the risk of cholera is high, such as during outbreaks.
authors.affiliation: Epicentre, Paris, France.|World Health Organization, Geneva, Switzerland.
authors.forename: Lise
authors.initials: L
authors.lastname: Grout
authors.affiliation: Epicentre, Paris, France.|European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.
authors.forename: Isabel
authors.initials: I
authors.lastname: Martinez-Pino
authors.affiliation: Médecins Sans Frontières, Geneva, Switzerland.
authors.forename: Iza
authors.initials: I
authors.lastname: Ciglenecki
authors.affiliation: Ministry of Health and Public Hygiene, Guinea.
authors.forename: Sakoba
authors.initials: S
authors.lastname: Keita
authors.affiliation: Ministry of Health and Public Hygiene, Guinea.
authors.forename: Alpha Amadou
authors.initials: AA
authors.lastname: Diallo
authors.affiliation: Ministry of Health and Public Hygiene, Guinea.
authors.forename: Balla
authors.initials: B
authors.lastname: Traore
authors.affiliation: Médecins Sans Frontières, Conakry, Guinea.
authors.forename: Daloka
authors.initials: D
authors.lastname: Delamou
authors.affiliation: Médecins Sans Frontières, Conakry, Guinea.
authors.forename: Oumar
authors.initials: O
authors.lastname: Toure
authors.affiliation: Epicentre, Paris, France.
authors.forename: Sarala
authors.initials: S
authors.lastname: Nicholas
authors.affiliation: Médecins Sans Frontières, Geneva, Switzerland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Rusch
authors.affiliation: Médecins Sans Frontières, Geneva, Switzerland.
authors.forename: Nelly
authors.initials: N
authors.lastname: Staderini
authors.affiliation: Médecins Sans Frontières, Geneva, Switzerland.
authors.forename: Micaela
authors.initials: M
authors.lastname: Serafini
authors.affiliation: Epicentre, Paris, France.
authors.forename: Rebecca F
authors.initials: RF
authors.lastname: Grais
authors.affiliation: Epicentre, Paris, France.|Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Luquero
mesh_terms: D000022:Abortion, Spontaneous / Q000453:epidemiology* / Q000209:etiology; D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000818:Animals; D002771:Cholera / Q000150:complications / Q000453:epidemiology / Q000517:prevention & control*; D022121:Cholera Vaccines / Q000008:administration & dosage; D015331:Cohort Studies; D004196:Disease Outbreaks; D005260:Female; D016701:Guinea / Q000453:epidemiology; D006801:Humans; D007223:Infant; D032541:Mass Vaccination; D008875:Middle Aged; D011247:Pregnancy; D011256:Pregnancy Outcome; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D022121:Cholera Vaccines