False pertussis outbreaks cause costly interventions

Overreliance on PCR testing cited

If you're thinking pertussis is the cause of a respiratory outbreak in your hospital or community, think twice. Pertussis was incorrectly determined to be the etiologic agent in two hospital outbreaks and one in the community in three states between 2004 and 2006, the Centers for Disease Control and Prevention warns.1

The false diagnosis can set off expensive control measures specifically designed for pertussis (e.g., case identification, antimicrobial treatment, furlough of ill people, and administration of PEP.) The findings underscore the need for thorough epidemiologic and laboratory investigation of suspected pertussis outbreaks before considering extensive control measures, the CDC advised. The outbreaks also cast doubt on relying solely on polymerase chain reaction (PCR) assays to confirm pertussis. The positive predictive value can be lower if PCR is used as a screening tool without culture confirmation during a suspected pertussis outbreak. "Overreliance on the results of PCR assays can lead to implementation of unnecessary and resource-intensive control measures," the CDC noted.


  1. Centers for Disease Control and Prevention. Outbreaks of Respiratory Illness mistakenly attributed to pertussis —- New Hampshire, Massachusetts, and Tennessee, 2004-2006. MMWR 2007; 56(33):842-846.