Comparison of memory B cell responses in Bangladeshi adults following single-dose and two-dose oral cholera vaccine, ShancholTM.
Abstract
Objective
Oral cholera vaccines (OCVs) provide short-term protection against cholera. The objective of this study was to assess the immune responses after each dose of ShancholTM vaccine.
Methods
We included 120 adults (18-45 years old) in this study and compared responses following administration of the standard two-dose regimen (14 days apart, n=40), a single-dose regimen (n=40), and an alternate two-dose regimen (one month apart, n=40) for up to one year.
Results
We found that all three groups of vaccinees developed prominent vibriocidal responses and plasma anti-lipopolysaccharide (LPS) IgG and IgA responses within seven days of vaccination, and vibriocidal responses remained elevated for more than one month. All groups of vaccinees developed IgA MBC responses to V. cholerae O1 LPS within 30 days of vaccination and remained detectable for 3 to 12 months. The cohort that received a single-dose of vaccine developed a significant IgG MBC response against V. cholerae O1 LPS at day 30. None of the groups exhibited an MBC response to O139 LPS compared with day 0.
Conclusion
Administering a single-dose induces comparable relevant immune responses as the two-dose regimen in 18-45 years old adults in highly cholera-endemic areas, such as Bangladesh. These findings may not be generalizable to children, immunologically naïve populations, or non-endemic settings.