Serum antibody responses against OSP in vaccinees of day 90 challenged group.

<p>Serum IgM, IgA and IgG responses targeting <i>V</i>. <i>cholerae</i> O1 Inaba or Ogawa OSP in recipients (n = 20) of oral cholera vaccine CVD 103-HgR who were then experimentally challenged with wild type <i>V</i>. <i>cholerae</i> O1 Inaba N16961 90 days after vaccination (denoted by top arrows). Day 0 is pre-vaccination and other dates are timed from vaccination. X axis indicates the time points of samples, while Y-axis denotes OSP-specific antibody responses. Each single dot indicates an individual OSP antibody value, horizontal bars indicate the geometric mean (GM), and error bars indicate 95% confidence intervals. <i>P</i> values represent differences of the mean between groups. Asterisks represent significant differences of responder frequency in Fisher’s exact test (*** <i>P ≤</i> 0.001, ** <i>P ≤</i> 0.01). We defined a responder as having a ≥1.5-fold increase in anti-OSP units compared to pre-vaccination value. Responder frequency is represented in parenthesis on x-axis.