Characteristics of studies included in the review (n = 32,253).

Ref- reference, N-number of individuals, ns- not stated; NPS- Nasopharyngeal swab; OPS- Oropharyngeal swab; c.alginate- Calcium Alginate; w-week, m-months, y-years, comm- community, opd-outpatient department, hosp-hospital, EPI -Expanded programme on immunisation clinic, DCC- day care centre, MCH- mother & child clinic,a any illness,b with respiratory tract infection,c perinatal follow up HIV clinic used control group,d routine check or immunisation,e medical conditions as well as routine checks,f minor illnesses no hospitalisations,g some swabbed once others swabbed more than once,h children and carers sick and well,I adults also swabbed age not specified,j hosp severe pneumonia,k tuberculosis patients,l year published,m patients returning for review after minor illness.