Pneumonia Etiology Research for Child Health (PERCH)


Existing knowledge on the etiologies of childhood pneumonia is largely based on studies from the 1980s and 1990s. With expanded use of pneumococcal conjugate vaccine and Haemophilus influenzae type b conjugate vaccine and changes in host and environmental factors, a new evidence base to guide treatment and prevention strategies is needed.


The Pneumonia Etiology Research for Child Health (PERCH) study is a case-control study led by IVAC that enrolled 4,232 cases and 5,325 controls between 2011-2014 at 9 sites in 7 countries (The Gambia, Mali, Kenya, Zambia, South Africa, Bangladesh and Thailand).

Cases were defined as children aged 1-59 months hospitalized with pre-2013 WHO-defined severe or very severe pneumonia.  Controls were randomly selected from the community and age-frequency matched to cases.  Multiple specimens were collected from each case and control and tested for over 30 pathogens.  Data were collected on clinical signs and symptoms, medical history, chest x-ray results, lab results, treatment, outcomes, and demographic, household, and environmental risk factors.

The objectives of PERCH were to:

  • determine the etiology of pneumonia by integrating results from multiple specimens
  • estimate the fraction of pneumonia attributable to pathogens for which vaccines are available or under development (e.g., pneumoniae, respiratory syncytial virus, parainfluenza virus, influenza and S. aureus) as well as other known, but poorly quantified causes of pneumonia in children
  • assess risk factors for pneumonia.

Foundational Papers

Primary Results paper

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