Population-based incidence of community-acquired pneumonia hospitalization in Hong Kong children younger than 5 years before universal conjugate pneumococcal immunization

Objectives We sought to document the incidence of pediatric hospitalization for bacterial pneumonia before universal childhood conjugate pneumococcal vaccination using two different methods of diagnosis. Methods By following the World Health Organization (WHO) chest radiography (CXR) protocol, two radiologists independently read the CXRs of a cohort of systematically recruited children younger than 5 years. The children had acute respiratory infections and were admitted to one of two hospitals that care for 72.5% of all pediatric admissions on Hong Kong Island. Medical records were reviewed for clinical manifestation and to identify bacterial pneumonia diagnosed by pediatricians. Results In children younger than 5 years, the incidences of bacterial pneumonia, as diagnosed by pediatricians and by the WHO CXR standard, were 775.7 per 100,000 population [95% confidence interval (CI, 591.8–998.3)] and 439.5 per 100,000 population (95% CI, 304.6–614.5), respectively. The study period was from 2002 to 2004. Conclusion This study provided a reliable baseline estimate of the hospitalization burden of pneumococcal pneumonia in Hong Kong children before the advent of universal conjugate pneumococcal vaccination.