TABLE 1

Characteristics of PCR-Positive Cases and PCR-Negative and KPNC Controls, January 2010 to December 2011

PCR-Positive Cases, n = 138 (%)PCR-Negative Controls, n = 899 (%)KPNC-Matched Controls, n = 54 339 (%)
Male gender72 (52.2)429 (47.7)28 351 (52.2)
Mean age ± SD (range)12.0 ± 1.4 (10–17)12.7 ± 1.8 (10–17)13.0 ± 1.8 (10–17)
Birth year
 19945 (3.6)93 (10.3)7472 (13.8)
 19953 (2.2)99 (11.0)8006 (14.7)
 199612 (8.7)123 (13.7)8293 (15.3)
 199723 (16.7)140 (15.6)9531 (17.5)
 199849 (35.5)197 (21.9)10 538 (19.4)
 199946 (33.3)247 (27.5)10 498 (19.3)
Age at anchored PCR test, y
 1012 (8.7)69 (7.7)3147 (5.8)
 1152 (37.7)235 (26.1)9627 (17.7)
 1233 (23.9)157 (17.5)10 254 (18.9)
 1322 (15.9)136 (15.1)9492 (17.5)
 1412 (8.7)134 (14.9)8655 (15.9)
 153 (2.2)89 (9.9)7306 (13.4)
 163 (2.2)72 (8.0)5224 (9.6)
 171 (0.7)7 (0.8)634 (1.2)
Year of PCR test
 2010102 (73.9)639 (71.1)40 164 (73.9)
 201136 (26.1)260 (28.9)14 175 (26.1)
Race
 American Indian/Alaska Native5 (3.6)11 (1.2)1969 (3.6)
 Asian or Pacific Islander10 (7.2)132 (14.7)3938 (7.2)
 Black6 (4.3)72 (8)2363 (4.3)
 Hispanic (regardless of race)39 (28.3)182 (20.2)15 357 (28.3)
 Imputed1 (0.7)21 (2.3)394 (0.7)
 White77 (55.8)481 (53.5)30 320 (55.8)
First 4 doses received
 All whole cell8 (5.8)226 (25.1)16 483 (30.3)
 Mix19 (13.8)178 (19.8)12 670 (23.3)
 All acellular111 (80.4)495 (55.1)25 185 (46.3)
No. of whole cell doses among those receiving mixed vaccine types
 14 (21.1)16 (9.0)999 (7.9)
 21 (5.3)15 (8.4)980 (7.7)
 314 (73.7)147 (82.6)10 692 (84.4)
Tdap vaccination status
 No92 (66.7)414 (46.1)18 534 (34.1)
 Yes46 (33.3)485 (53.9)35 805 (65.9)