Table 1.

Comparison of methods of pneumonia surveillance system and birth cohort

	Facility-based pneumonia surveillance system	DCHS Birth cohort15
Time period	June 2012–September 2013 (calendar-year incidence calculation: 1 September 2012–31 August 2013	29 May 2012–31 May 2014
Study population	All children <5 years resident in the catchment area; incidence calculated for children <1 year of age	Birth cohort participants in first year of life; 697 infants born between 29 May 2012 and 31 May 2014
Estimation of person-time at risk	Estimated 1292 children <1 year of age from Department of Health population statistics	Calculated for each individual from date of birth until death/disenrolment/first birthday
Method of pneumonia case detection	Clinics: PHC nurse identification of IMCI pneumonia at each facility, and basic data collection form completed Hospital: record review of children resident in catchment area attending hospital	Examination by trained study nurse; real-time interview of mother; record review of medical notes Retrospective inclusion of cases: if medical records indicated that they met WHO pneumonia criteria

DCHS, Drakenstein Child Health Study; ICMI, Integrated Management of Childhood Illness; PHC, primary healthcare.