Table 2.
Respiratory Virus Detections Among Case Patients Included in the Analysis
| Respiratory Virus Detected | All LRTI and Pneumonia Cases Analyzed, No. (%) (N = 17 416)a |
LRTI and Pneumonia Cases by Clinical Syndrome, No. (%) | LRTI and Pneumonia Cases by Patient’s Hospitalization Status, No (%) | ||
|---|---|---|---|---|---|
| Nonpneumonia LRTI (n = 4644) | Pneumonia (n = 12 772) | Not Hospitalized (n = 7634) | Hospitalized (n = 9782) | ||
| Any virus detected, by specific virus identified | |||||
| Influenza A | 3956 (22.7) | 1974 (42.5) | 1982 (15.5) | 1905 (25.0) | 2051 (21.0) |
| Influenza B | 1141 (6.6) | 607 (13.1) | 534 (4.2) | 588 (7.7) | 553 (5.7) |
| RSV | 1462 (8.4) | 320 (6.9) | 1142 (8.9) | 562 (7.4) | 900 (9.2) |
| HCoVs (229E, HKU1, OC43, NL63) | 975 (5.6) | 204 (4.4) | 771 (6.0) | 416 (5.4) | 559 (5.7) |
| Parainfluenza viruses (1–4) | 1259 (7.2) | 328 (7.1) | 931 (7.3) | 539 (7.1) | 720 (7.4) |
| Adenoviruses | 172 (1.0) | 37 (0.8) | 135 (1.1) | 80 (1.0) | 92 (0.9) |
| HMPV | 1460 (8.4) | 184 (4.0) | 1276 (10.0) | 602 (7.9) | 858 (8.8) |
| Enteroviruses | 3431 (19.7) | 643 (13.8) | 2788 (21.8) | 1533 (20.1) | 1898 (19.4) |
| Any respiratory virus | 13 856 (79.6) | 4297 (92.5) | 9559 (74.8) | 6225 (81.5) | 7631 (78.0) |
| Single virus detected | |||||
| Influenza A | 3693 (21.2) | 1859 (40.0) | 1834 (14.4) | 1793 (23.5) | 1900 (19.4) |
| Influenza B | 1030 (5.9) | 557 (12.0) | 473 (3.7) | 546 (7.2) | 484 (4.9) |
| RSV | 1283 (7.4) | 284 (6.1) | 999 (7.8) | 504 (6.6) | 779 (8.0) |
| HCoVs (229E, HKU1, OC43, NL63) | 743 (4.3) | 125 (2.7) | 618 (4.8) | 314 (4.1) | 429 (4.4) |
| Parainfluenza viruses (1–4) | 1174 (6.7) | 305 (6.6) | 869 (6.8) | 504 (6.6) | 670 (6.8) |
| Adenoviruses | 128 (0.7) | 24 (0.5) | 104 (0.8) | 60 (0.8) | 68 (0.7) |
| HMPV | 1353 (7.8) | 171 (3.7) | 1182 (9.3) | 564 (7.4) | 789 (8.1) |
| Enteroviruses | 3149 (18.1) | 572 (12.3) | 2577 (20.2) | 1412 (18.5) | 1737 (17.8) |
| No virus detected (negative for all)b | 3560 (20.4) | 347 (7.5) | 3213 (25.2) | 1409 (18.5) | 2151 (22.0) |
Abbreviations: HCoVs, human coronaviruses; HMPV, human metapneumovirus; LRTI, lower respiratory tract infection; RSV, respiratory syncytial virus.
Totals do not necessarily reflect the true prevalence of each virus (or no viruses) among case patients, as we drew a 20% sample of virus-negative case patients. For LRTIs, diagnosis codes from the International Classification of Diseases, Tenth Revision, Clinical Modification, are provided in Supplementary Table 1).
We analyzed data from a randomly sampled subset of all virus-negative case patients.