Immune Responses to an Oral Cholera Vaccine in Internally Displaced Persons in South Sudan

Sci Rep. 2016 Oct 24;6:35742. doi: 10.1038/srep35742.

Abstract

Despite recent large-scale cholera outbreaks, little is known about the immunogenicity of oral cholera vaccines (OCV) in African populations, particularly among those at highest cholera risk. During a 2015 preemptive OCV campaign among internally displaced persons in South Sudan, a year after a large cholera outbreak, we enrolled 37 young children (1-5 years old), 67 older children (6-17 years old) and 101 adults (≥18 years old), who received two doses of OCV (Shanchol) spaced approximately 3 weeks apart. Cholera-specific antibody responses were determined at days 0, 21 and 35 post-immunization. High baseline vibriocidal titers (>80) were observed in 21% of the participants, suggesting recent cholera exposure or vaccination. Among those with titers ≤80, 90% young children, 73% older children and 72% adults seroconverted (≥4 fold titer rise) after the 1st OCV dose; with no additional seroconversion after the 2nd dose. Post-vaccination immunological endpoints did not differ across age groups. Our results indicate Shanchol was immunogenic in this vulnerable population and that a single dose alone may be sufficient to achieve similar short-term immunological responses to the currently licensed two-dose regimen. While we found no evidence of differential response by age, further immunologic and epidemiologic studies are needed.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Adolescent
  • Antibodies, Bacterial / immunology
  • Antibody Formation / immunology*
  • Child
  • Child, Preschool
  • Cholera / epidemiology
  • Cholera / immunology*
  • Cholera Vaccines / immunology*
  • Disease Outbreaks / prevention & control
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • South Sudan / epidemiology
  • Vaccination / methods
  • Vaccines, Inactivated / immunology
  • Vibrio cholerae / immunology

Substances

  • Antibodies, Bacterial
  • Cholera Vaccines
  • Vaccines, Inactivated
  • shanchol