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

Anita S. Iyer, Malika Bouhenia, John Rumunu, Abdinasir Abubakar, Randon J. Gruninger, Jane Pita, Richard Lako Lino, Lul L. Deng, Joseph F. Wamala, Edward T. Ryan, Stephen Martin, Dominique Legros, Justin Lessler, David A. Sack, Francisco J. Luquero, Daniel T. Leung, Andrew S. Azman

Research output: Contribution to journalArticle

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.

Original languageEnglish (US)
Article number35742
JournalScientific reports
Volume6
DOIs
StatePublished - Oct 24 2016

ASJC Scopus subject areas

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    Iyer, A. S., Bouhenia, M., Rumunu, J., Abubakar, A., Gruninger, R. J., Pita, J., Lino, R. L., Deng, L. L., Wamala, J. F., Ryan, E. T., Martin, S., Legros, D., Lessler, J., Sack, D. A., Luquero, F. J., Leung, D. T., & Azman, A. S. (2016). Immune Responses to an Oral Cholera Vaccine in Internally Displaced Persons in South Sudan. Scientific reports, 6, [35742]. https://doi.org/10.1038/srep35742