This case is a cluster of 6 unidentified patients who tested positive for pertussis following administration of DTaP (manufacturer and lot number not reported). Initial report was received from a health care professional on 30 January 2012. Six unidentified patient's (gender, date of birth and ages not reported) had received DTaP (manufacturer, lot number, site, route and date of administration not reported). Five of the patient's tested positive with the polymerase chain reaction (PCR) test for bordatella pertussis and one child tested positive with PCR for parapertussis. No further information was available at the time of the report. The patients' outcomes were not reported. Follow-up information was received on 09 February 2012. The reporter also reported another patient which experienced pertussis following administration of DTaP (manufacturer and lot number not reported). That adverse event was captured in case 2012-01617. Follow-up information was received from a health care professional on 24 February 2012. Based upon the new information provided, this case has been upgraded to serious. The six patients' were identified. The other five patients are captured in cases 2012-02345, 2012-02347, 2012-02348, 2012-02350 and 2012-02351. A 4-year-old female patient received a dose of DAPTACEL (lot number C3474AA, route and site of administration not reported) on 16 February 2011. On the same date, the patient also received an injection of PREVNAR (manufactured by Wyeth, lot number, route and site not reported) and VARIVAX (manufactured by Merck, lot number, route and site not reported). The patient's vaccine history included 3 previous injections of PEDIARIX (manufactured by GlaxoSmithKline) on 11 February 2007, 15 April 2007 and 15 August 2007 and an unspecified DTaP vaccine (manufacturer, lot number, route and site not reported) on 27 February 2008. The patient was seen on 09 January 2012 with complaints of a cough for 3 weeks that was barky, raspy and worse at night, fever, an ear ache and congestion. The patient reportedly gags with the cough, almost vomits and sounds wet. The patient's brother and father also have the same cough. Upon examination, the patient was found to have erythema with very scant exudate on tonsils and mildly tender cervical lymphadenopathy. Pre-nebulizer treatment: no crackles and one wheeze in the right lower lobe heard in front of chest. Post-nebulizer treatment: more wheezes in right lower lobe with questionable crackle. The physician's assessment was cough, bronchitis NOS, pharyngitis acute and reactive airways disease (RAD). Pertussis and early pneumonia were suspected. The patient was treated with azithromycin, albuterol solution and ROBITUSSIN AC syrup to cover pertussis and pneumonia. A nasopharyngeal swab and rapid strep test was performed. The patient was seen again on 11 January 2012 because the cough was getting worse. The patient's nasopharyngeal swab PCR results on 12 January 2012 were "Bordatella pertussis DNA detected. (Does not distinguish between B. pertussis and B. homesii)." The patient had no known drug allergies (NKDA) and took no concomitant medications. The patient had a past medical history of jaundice at birth, epicanthal folds on eyes, questionable Simean crease, delayed gross motor development at 6 months, normal HR chromosomes, gastroeseophageal reflux disease (GERD), vulvitis, dysuria, vaginitis, croup, strep infection, and a fractured toe. The patient was up-to-date with HepB, Hib, IPV/OPV, PREVNAR, MMR, Varicella, Rota and HepA vaccinations. No further information was available at the time of the report. The patient's outcome was not reported. Documents held by sender: Medical Records.