Volume 15, Number 8—August 2009
Research
Bordetella pertussis Strains with Increased Toxin Production Associated with Pertussis Resurgence
Frits R. Mooi
, Inge H.M. van Loo, Marjolein van Gent, Qiushui He, Marieke J. Bart, Kees J. Heuvelman, Sabine C. de Greeff, Dimitri Diavatopoulos, Peter Teunis, Nico Nagelkerke, and Jussi Mertsola
, Inge H.M. van Loo, Marjolein van Gent, Qiushui He, Marieke J. Bart, Kees J. Heuvelman, Sabine C. de Greeff, Dimitri Diavatopoulos, Peter Teunis, Nico Nagelkerke, and Jussi MertsolaTable 3
Increases in illness and death caused by pertussis in 2 periods with low and high frequencies of ptxP3 strains in the Netherlands*
| Parameter | ptxP3 frequency, % | Hospitalizations/100,000 | Deaths/100,000 | Lethality† |
|---|---|---|---|---|
| 1981–1992 | 1.6 | 1.38 | 0.00057 | 0.00041 |
| 1993–2004 | 54.5 | 1.95 | 0.00582 | 0.00299 |
| Increase | 33.1 | 1.41 (1.34–1.49) | 10.21 (1.31–79.11) | 7.23 (0.93–56.07) |
| p value | <0.0001 | 0.0058 | 0.03 |
*ptxP, pertussis toxin promoter. Numbers in parentheses are 95% confidence intervals.
†Lethality = no. of deaths / no. of hospitalizations.
