Table 1.

Sociodemographic and clinical characteristics of the included studies.

Characteristics	N = 112	%
Age range
2 years	35	31.3
<5 years	22	19.6
<10 years	4	3.6
<15 years	20	17.9
<18 years	27	24.1
Not reported	4	3.6
Male range (%)	39.1–73.8%
Period of inclusion of participants; range	January 2015–December 2022
Year of publication; range	2017–2023
Study design
Cross-sectional	75	67
Longitudinal	37	33
Sampling method
Consecutive	110	98.2
Random	2	1.8
Timing of data collection
Ambispective	4	3.6
Prospective	58	51.8
Retrospective	50	44.6
Study bias
Low risk	71	63.4
Moderate risk	41	36.6
WHO region
African	7	6.3
Americas	13	11.6
Eastern Mediterranean	3	2.7
European	47	42
South–East Asia	8	7.1
Western Pacific	34	30.4
Type of assay
Immune assays ¥	22	19.6
Molecular assays ¥¥	85	75.9
Mixed assays ¥¥¥	5	4.5
Diagnostic technique $
Antigen	6	5.4
Direct immunofluorescence	16	14.3
Mixed ¥¥¥	5	4.5
Multiplex PCR	14	12.5
Multiplex RT–PCR	18	16.1
PCR	16	14.3
qPCR	2	1.8
RT–PCR	31	27.7
RT–qPCR	4	3.6
Sample type
Mixed *	7	6.3
Nasal secretions	9	8
Nasopharyngeal secretions	62	55.4
Nasopharyngeal secretions or BLF	11	9.8
Not reported	8	7.1
Oropharyngeal swab	7	6.3
Sputum	3	2.7
Throat swab	5	4.5

¥ Immune assays: antigen testing or direct immunofluorescence. ¥¥ Molecular assays: multiplex PCR, multiplex RT–PCR, PCR, qPCR, RT–PCR, or RT–qPCR. ¥¥¥ Mixed assays: antigen testing/RT–PCR, direct immunofluorescence/RT–qPCR/antigen testing, direct immunofluorescence/RT–PCR, or indirect immunofluorescence/PCR. $ The indicated diagnostic technique is according to the authors’ description. * Mixed specimens: nasopharyngeal secretions and nasal secretions or nasal and throat secretions. Abbreviations: WHO, World Health Organization; BLF, bronchoalveolar lavage fluid.