Pertussis hospitalizations among Oregon infants, february 2009 – september 2012

Background: During 2012, 907 cases of pertussis were reported in Oregon — the highest number since 1953. Infants have consistently had the highest incidence: 259/100,000 persons. During February 2009 – September 2012, 87 (33%) of the 263 infant cases were hospitalized, while the same was true for only 22 (1.5%) of the 1425 non-infant cases.

Methods: Review of medical records of infants hospitalized with pertussis reported in Oregon during a 44-month period.

Results: Reviewed 80 (92%) of the 87 medical charts. Median duration of hospitalization was 4 (range, 1–128) days. Symptoms included cough (100%), paroxysms (90%), apnea (80%), posttussive vomiting (69%), and whoop (51%). Twenty (45%) developed pneumonia. Other complications included seizures (4 patients), pulmonary hypertension (2 patients), hemorrhages in the CNS and acute encephalopathy (1 patient). Supplemental oxygen was administered to 30 (38%) infants. Twenty-three (29%) infants were admitted to ICU; five required mechanical ventilation. Another infant was supported with extracorporeal membrane oxygenation for > 40 days. One infant <6 months old died. One patient was discharged on oxygen. Fifty-four (62%) of the infants were <2 months old. Of the 24 infants >2 months of age, 14 (58%) were unvaccinated, and 7 were appropriately vaccinated for their age.

Conclusions: Most of the suffering from pertussis is experienced by infants too young to be vaccinated. To reduce exposure to pertussis the best practices remain vaccination of all persons in close contact with infants, pregnant women during the last trimester, timely vaccination of infants, early treatment of cases and antibiotic prophylaxis around infants.