Avidities of anti-PT IgG and anti-FHA IgG among young children, older children, and adults.

<p>The avidity indexes (AI) were determined in IgG fractions that were purified from serum samples, which were collected in 2014. The age groups were 4–7 years, 10–14 years, and 35–44 years. Bars indicate the geometric mean AI values. Numbers in parentheses indicate the number of samples that were analyzed. Y, years; NS, not significant. <i>P</i>-values were determined using the Steel-Dwass test.