TABLE 3.
Distribution of positive and negative cases with laboratory-confirmed pertussis for participants ≥7 years olda
Method of diagnosis (cutoff) | No. of cases | No. of noncases |
---|---|---|
Positive pertussis test | ||
ptxA-Pr PCR | 13 | 3 |
IS481 PCR | 37 | 17 |
Single serology (≥125 EU/ml) | 53 | 9 |
Paired serology (×4b) | 13 | 12 |
Positive pertussis test using combination of single serology (≥125 EU/ml) with: | ||
Paired serology (×4) | 66 | 12 |
PtxA-Pr PCR | 62 | 12 |
IS481 PCR | 73 | 23 |
Subjects were contacts of infant pertussis cases with complete laboratory data (n = 195). Complete data include symptoms, serology, and PCR (IS481 and ptx-Pr) at enrollment and symptoms and serology at follow-up visit 1 month later.
×4, fourfold change in titer.
cCase definition: laboratory-confirmed symptomatic contact. There were 82 cases and 113 noncases.