Table 4.

IgG antibody levels against pertussis toxin among 68 subjects with a positive diagnosis of pertussis in 2009a

Age group (yr)Mean titer (IU/ml)SDTotal no. of casesNo. (%) of cases with indicated titer (IU/ml)
>200>400b
0–4232NA11 (100)0 (0)
5–9NANA00 (0)0 (0)
10–1428510376 (86)1 (14)
15–193401281210 (83)5 (42)
20–2429310732 (67)0 (0)
25–2925216253 (60)1 (20)
30–3419212421 (50)0 (0)
35–3922613074 (57)1 (14)
40–4428714496 (67)2 (22)
45–49328127108 (80)4 (40)
50–5430211243 (75)1 (25)
55–5916416131 (33)0 (0)
60–64317NA11 (100)0 (0)
65–6928117022 (100)0 (0)
70–7456NA10 (0)0 (0)
>75427NA11 (100)1 (100)
UnknownNANA00 (0)0 (0)
Total2851296849 (72)16 (24)
  • a Results were obtained by using NIBSC 06/140 standard antiserum and the Virotech anti-PT ELISA. NA, not applicable.

  • b The groups with the highest percentages of stronger antibody responses are highlighted in boldface.