Incidence and severity of childhood pneumonia in the Drakenstein Child Lung Health Study, a birth cohort in South Africa

Abstract

Background: Childhood pneumonia remains the major cause of global under-5 mortality. Conjugate vaccinations against Streptococcus pneumoniae (PCV13)was introduced into the South African primary health care program in 2009, while immunisation against Haemophilus influenzae b has been in place for a decade. This study investigated the incidence and severity of pneumonia in a South African birth cohort with high coverage for these vaccines. Methods & Materials: Active pneumonia case detection was performed from June 2012 to November 2013, in infants enrolled in the Drakenstein Child Lung Health study, a birth cohort study in a peri-urban area of South Africa. Pneumonia case definitions and treatment were according to IMCI and national guidelines; ambulatory and hospitalised cases were included. Results: Amongst 555 births, 369 child-years of follow-up were accrued with median follow-up of 33 weeks (IQR 19 – 49 weeks). 108 pneumonia episodes occurred in 87 children, an incidence of 0.29 episodes per child-year (e/cy), 95%CI 0.24 – 0.35. First pneumonia events occurred before 14-week vaccination in 45 children (42%); the earliest event occurred at 21 days. There were 43 cases of hospitalised pneumonia, (incidence 0.12 e/cy, 95% CI 0.08 – 0.16) and 65 ambulatory episodes (incidence 0.18 e/cy, 95%CI 0.14 – 0.22). Hospitalised cases were younger than ambulatory cases: median age 13 weeks (IQR 6 – 27), vs 21 weeks, (IQR 12 – 24), p=0.03. Median length of hospitalisation was 3 days, (IQR 2 -5 days). The in-hospital case fatality was 5%; there were no deaths amongst ambulatory cases and no case progressed to require hospitalisation. Conclusion: There was a high incidence of pneumonia and of severe disease despite high PCV coverage in this area Funding: Bill and Melinda Gates Foundation; SA Thoracic society GSK Fellowship; Federation of Infectious Diseases Societies of South Africa