Table 1.
Summary of Key Characteristics of Included Studies
| Characteristic | No. (%) (n = 154) |
|---|---|
| World Health Organization region | |
| Americas | 59 (37) |
| Europe | 53 (32) |
| Western Pacific | 38 (24) |
| Africa | 3 (1.9) |
| South-East Asia | 3 (1.9) |
| Study design | |
| Cross-sectional | 137 (89) |
| Surveillance | 8 (5.2) |
| Prospective cohort | 4 (2.6) |
| Case-control | 3 (1.9) |
| Retrospective cohort | 1 (0.6) |
| Randomized controlled trial | 1 (0.6) |
| Age group | |
| Adults and children | 80 (52) |
| Adults, 18 y and older | 25 (16) |
| Not reported, eg, based on stored samples | 49 (32) |
| Clinical setting | |
| Inpatient only, hospitalized and ICU | 29 (19) |
| Emergency department only | 7 (4.5) |
| Outpatient only, clinics and primary care centers | 8 (5.2) |
| Inpatient and emergency department, mixed | 3 (1.9) |
| Outpatient, inpatient, and emergency department, mixed | 8 (5.2) |
| Others, community-based and clinical trial sites | 4 (1.9) |
| Not reported | 95 (62) |
| Clinical presentation of the population studied | |
| LRTI onlya | 30 (19.5) |
| URTI only | 13 (8.4) |
| URTI or LRTI | 42 (27.3) |
| LRTI exacerbating preexisting conditions | 5 (3.2) |
| Otherb | 3 (1.9) |
| Not reported | 61 (39.6) |
| Specimen typec | |
| Nasopharyngeal swab | 102 (47.6) |
| Nasopharyngeal aspirate | 49 (31.8) |
| Bronchoalveolar lavage | 40 (18.7) |
| Oropharyngeal swab | 36 (16.8) |
| Othersd | 27 (12.6) |
| Sputum | 23 (10.7) |
| Nasal swab | 19 (12.3) |
| Nasal wash/aspirate | 12 (5.6) |
| Paired serology sample | 6 (2.8) |
| Not specified | 3 (1.4) |
| Saliva | 2 (0.6) |
| Diagnostic test | |
| Multiplex RT-PCR | 113 (68.5) |
| Singleplex RT-PCR | 26 (15.8) |
| Viral culture | 36 (21.8) |
| Direct fluorescent antibody test | 20 (12.1) |
| Rapid antigen detection tests | 18 (10.9) |
| Otherse | 10 (6.5) |
| Conventional PCR | 6 (3.6) |
| Serology | 6 (3.6) |
Abbreviations: ICU, intensive care unit; LRTI, lower respiratory tract infection; RT-PCR, reverse transcription-polymerase chain reaction; URTI, upper respiratory tract infection.
Includes pneumonia, acute bronchitis, bronchiolitis, and influenza-like illnesses.
Patients with respiratory illness or suspected respiratory illness with unclear category.
Eighty studies used a combination of respiratory samples for testing.
Unspecified upper respiratory swab, stored nucleic acid extract, unspecified respiratory secretions, pleural fluid, mouth wash, endotracheal tube specimen, and bronchial brushings.
Loop-mediated isothermal amplification (LAMP) = 4, nucleic acid sequence-based amplification (NASBA) = 3, reverse transcription strand invasion-based amplification (RT-SIBA) = 2 studies, Sanger sequencing = 1.