Vaccine preventable community-acquired pneumonia in hospitalized children in Northwest China

Community-acquired pneumonia (CAP) is a major cause of morbidity in industrialized countries and morbidity/mortality in developing countries. In China, comprehensive studies of the etiology of CAP in children aged between 2 months and 14 years who are serious enough to require hospitalization are lacking. Previous studies have been limited in child age range, focused on fatal cases, and/or limited in etiologies sought. An understanding of the etiologies is needed for development of best prevention and management practices.

The aim of this study was to prospectively determine during a 12-month period the etiology of CAP in hospitalized children in a center in Northwest China.

A prospective 12-month study (2004-2005) of CAP cases in children who were 2 months to 14 years of age admitted to the Second Hospital of Lanzhou University, China. Testing included admission and 1-month postdischarge serum for viral and bacterial serologic analyses (respiratory syncytial virus, influenza A and B, paraflu 1-3, adenovirus; Streptococcus pneumoniae, Haemophilus influenza B, Mycoplasma, and Moraxella. catarrhalis), blood culture, a nasopharyngeal aspirate for viral antigen testing, and a chest radiograph on admission and 1 month postdischarge. The study was funded by Lanzhou University. The study was performed in compliance with the guidelines of the institutional review board of the Second Hospital of Lanzhou University.

CAP was the admitting diagnosis for 29% of all admissions during the 12-month study. Of the 884 CAP cases, 821 (93%) were enrolled and completed the study. The age range was 2 months to 14 years; mean age was 2.3 years; 40% were <1 year. The average length of stay was 9.2 days (range, 6-20) but varied by age and etiology. Fourteen percent had received antibiotics before admission and 14% had underlying illnesses; 12% required intensive care unit treatment and 5 died. A microbial etiology for CAP was identified in 547 (67%); viral 535 (43%), bacterial 228 (27%), mixed viral bacterial 107 (13%), mixed viral in 1%, and mixed bacterial in 1%. The etiology varied by age; respiratory syncytial virus was most common in <1 year, S. pneumoniae and Hib 1-3 years, and Mycoplasma 5 years. Three potentially vaccine preventable etiologies accounted for 35% of the cases: influenza 9%, Hib 12%, and S. pneumonia 14%.

CAP is a major cause of childhood admission in China. Given the etiologic findings in this study, potentially 25% to 35% of cases could be prevented if seasonal influenza vaccine and conjugated H. influenza b and conjugated pneumococcal vaccines were introduced into routine practice.