Figure 2. Standardized number of serotypes above thresholds.

Box plots of standardized number of serotypes above thresholds (IgG ≥0.35 µg/ml and OPA titers ≥8) at 3.5 years in each of the groups [standardized to 13 serotypes]. The median is shown as a line across the box with the box representing the lower and upper quartiles. Whiskers extend to the maximum or minimum values within 1.5 times the IQR above and below the 3^rd and 1^st quartile, respectively. Points outside this range are represented as dots.