Incidence of pneumonia, bacteremia, and invasive pneumococcal disease in Pakistani children

Objective To determine the incidence of pneumonia, bacteremia, and invasive pneumococcal disease (IPD) in Pakistani children <5 years old. Methods Household surveillance from 1st February 2007 to 12th May 2008 was conducted in two low-income, coastal communities of Karachi. Community health workers referred each sick child <5 years old to the local clinic. Blood culture was obtained whenever possible from children meeting inclusion criteria. Results Overall, 5570 children contributed 3949 observation years. There were 1039 clinical cases of pneumonia, of which 54 were severe pneumonia and four cases of very severe disease according to WHO criteria. The overall pneumonia incidence was 0.26 (95% CI: 0.25-0.28) episodes per child-year. A pathogen was isolated from the blood of 29 (2.8%) pneumonia cases. Bacteremia incidence was 912 (95% CI: 648-1248) episodes per 100 000 child-years with a case fatality rate of 8%. The detected IPD incidence was 25 (95% CI: 1-125) episodes per 100 000 child-years. The under-five mortality rate was 55 per 1000 live births, with pneumonia causing 12 (22%) deaths among children <5 years old. Conclusion Clinical pneumonia is common in Pakistani children, with one in four deaths attributable to the disease. Bacteremia occurs at a high rate but surveillance for pneumococcus underestimates the burden of IPD.