Table 1. Seroprevalence of anti-B. pertussis IgA and IgM titers among different age groups.

Age group (years)	n	Anti-B. pertussis IgA titers		Anti-B. pertussis IgM titers
		Mean ± SD	P valuea	Mean ± SD	P valuea
1–5	37	1.6 ± 1.1	-	5.5 ± 2.6	-
6–10	39	2.9 ± 2.2	0.007	7.7 ± 3.5	0.019
11–15	43	3.6 ± 3.0	<0.001	7.9 ± 3.2	0.006
16–20	34	4.1 ± 3.2	<0.001	7.3 ± 3.6	ns
21–25	39	4.0 ± 2.8	<0.001	7.2 ± 2.4	0.042
26–30	38	4.0 ±2.5	<0.001	6.7 ± 2.5	ns
31–35	35	3.4 ± 2.9	<0.001	5.9 ± 2.3	ns
36–40	42	3.8 ± 2.4	<0.001	5.2 ± 2.0	ns
41–45	43	4.0 ± 3.5	<0.001	4.8 ± 1.9	ns
46–50	34	6.0 ± 6.3	<0.001	4.5 ± 1.8	ns
51–55	39	4.7 ± 4.2	<0.001	4.7 ± 2.0	ns
56–60	37	4.1 ± 5.1	<0.001	4.1 ± 1.6	ns

NOTE. Antibody titers are represented in Novagnost units (NTU).

^a Dunn’s multiple comparison test; the 1–5 years age group was used as a control group for comparison. Significant at P value < 0.05, ns: not significant.