a1 Department of Pediatrics, The University of Tokyo Hospital, Tokyo, Japan
a2 Department of Health Management and Policy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
a3 Department of Preventive Medicine and Community Health, University of Occupational and Environmental Health, Fukuoka, Japan
We examined pertussis hospitalizations among infants aged <1 year between 2006 and 2008 using the nationwide inpatient database in Japan. A total of 660 infants hospitalized for pertussis were identified. Peak incidence occurred at age 1 month and infants aged 0–2 months (too young for pertussis vaccination) and ≥3 months (eligible for at least one dose of vaccination) accounted for 44·5% and 55·5% of hospitalizations, respectively. Complications related to pertussis were found in 165 (25·0%) cases, including one death; the age at admission did not differ significantly between patients with and those without complications (mean age 4·1 vs. 4·5 months, P=0·12). Seventeen patients required mechanical ventilation. Of the 17 cases, 14 infants were aged <3 months and three infants were aged ≥3 months. Our findings highlight that the vaccination schedule against pertussis may often be delayed in Japan.
(Accepted September 12 2011)
(Online publication October 05 2011)