Should the pertussis case definition for public health reporting be refined?
BACKGROUND
The surveillance case definition for confirmed pertussis requires that an individual with a positive polymerase chain reaction (PCR) result for Bordetella pertussis have 2 weeks or more of cough and at least one of the following: paroxysmal coughing, inspiratory "whoop," or posttussive vomiting.


OBJECTIVE
Determine (1) proportion of individuals with a positive PCR result who met additional criteria for surveillance confirmed pertussis, (2) whether the likelihood of PCR-positive individuals meeting additional elements of surveillance case definition varied by age or vaccination status, and (3) whether elements of the current case definition influence the likelihood of pertussis confirmation in PCR-positive individuals.


METHODS
Pertussis PCR results were compared with case investigation data.


RESULTS
Eighty-eight percent (165/188) of PCR-positive individuals met requirements for confirmed pertussis. Sixty-one percent (14/23) of PCR-positive individuals who had less than 2 weeks but more than 1 week of cough had at least one other reported sign or symptom. Fourteen (100%) reported paroxysmal coughing, 7 (50%) "whoop," and 7 (50%) posttussive vomiting. Infants who met case definition were more likely to have reported apnea than were older individuals (15/17 vs 45/86, OR = 6.8, 95% CI = 1.4-64.2).


CONCLUSIONS
Decreasing cough duration from 2 weeks or more to more than 1 week would result in 95 percent of those with positive PCR results meeting confirmation criteria for pertussis. Apnea should be considered an additional sign for pertussis confirmation in infants.
Shakib
Julie H
JH
Department of Pediatrics, General Pediatric Division, University of Utah, Salt Lake City, UT, USA. julie.shakib@hsc.utah.edu
Wyman
Lisa
L
Gesteland
Per H
PH
Staes
Catherine J
CJ
Bennion
D W
DW
Byington
Carrie L
CL
D000293:Adolescent; D000328:Adult; D001886:Bordetella pertussis / Q000235:genetics / Q000302:isolation & purification; D002648:Child; D002675:Child, Preschool; D018563:Disease Notification; D006801:Humans; D016133:Polymerase Chain Reaction; D011159:Population Surveillance / Q000379:methods; D015980:Public Health Practice; D014917:Whooping Cough / Q000175:diagnosis* / Q000503:physiopathology; D055815:Young Adult