Correlations among serological measures across the 20 different villages sampled throughout The Gambia. (A) Seroprevalence measurements from the wet and dry seasons are similar (dotted line shows x = y) and very highly correlated. (B) Derived lambda parameters from the age-seroprevalence distributions tend to be slightly higher for the wet season estimate, with outlying data for two labelled villages. (C) Wet season correlation between seroprevalence and derived lambda parameter, showing two labelled villages with an elevated lambda estimate. (D) Dry season correlation between seroprevalence and derived lambda parameter. Estimates of the lambda parameter with 95% confidence intervals for each season are given in full in Additional file 3.