Background
Methods
Results
Included patients: distribution, characteristics and influenza positives and negatives
Category | St. Pet | Moscow | Kazakhstan | Czech Rep. | Canada | Romania | Turkey | Valencia | Tunisia | Suzhou/ Shanghai | India | Mexico | South Africa | Total | ||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
n | % | n | % | n | % | n | % | n | % | N | % | n | % | n | % | n | % | n | % | n | % | n | % | n | % | n | % | |
Screened admissions | 2012 | 2244 | 661 | 201 | 2450 | 902 | 917 | 6913 | 106 | 1264 | 693 | 1480 | 2124 | 21967 | ||||||||||||||
Exclusion criteria | ||||||||||||||||||||||||||||
Non resident | 2 | 0.1 | 167 | 7.4 | 0 | 0.0 | 3 | 1.5 | 1 | 0.0 | 394 | 43.7 | 78 | 8.5 | 25 | 0.4 | 9 | 8.5 | 180 | 14.2 | 5 | 0.7 | 294 | 19.9 | 0 | 0.0 | 1158 | 5.3 |
institutionalised | 1 | 0.0 | 19 | 0.8 | 21 | 3.2 | 0 | 0.0 | 461 | 18.8 | 1 | 0.1 | 20 | 2.2 | 358 | 5.2 | 0 | 0.0 | 1 | 0.1 | 0 | 0.0 | 9 | 0.6 | 0 | 0.0 | 891 | 4.1 |
Previous discharged < 30 days | 3 | 0.1 | 114 | 5.1 | 44 | 6.7 | 7 | 3.5 | 145 | 5.9 | 68 | 7.5 | 173 | 18.9 | 1131 | 16.4 | 5 | 4.7 | 65 | 5.1 | 33 | 4.8 | 216 | 14.6 | 0 | 0.0 | 2004 | 9.1 |
Unable to communicate | 10 | 0.5 | 136 | 6.1 | 0 | 0.0 | 11 | 5.5 | 0 | 0.0 | 0 | 0.0 | 50 | 5.5 | 367 | 5.3 | 0 | 0.0 | 30 | 2.4 | 0 | 0.0 | 126 | 8.5 | 282 | 13.3 | 1012 | 4.6 |
Not giving consent | 44 | 2.2 | 8 | 0.4 | 49 | 7.4 | 13 | 6.5 | 0 | 0.0 | 1 | 0.1 | 15 | 1.6 | 275 | 4.0 | 0 | 0.0 | 3 | 0.2 | 1 | 0.1 | 54 | 3.6 | 90 | 4.2 | 553 | 2.5 |
No ILI symptoms ≥5 years | 0 | 0.0 | 42 | 1.9 | 9 | 1.4 | 37 | 18.4 | 573 | 23.4 | 41 | 4.5 | 140 | 15.3 | 2164 | 31.3 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 108 | 7.3 | 215 | 10.1 | 3329 | 15.2 |
Admission within 7 days of symptoms onset | 4 | 0.2 | 124 | 5.5 | 279 | 42.2 | 8 | 4.0 | 137 | 5.6 | 4 | 0.4 | 3 | 0.3 | 335 | 4.8 | 4 | 3.8 | 301 | 23.8 | 2 | 0.3 | 216 | 14.6 | 170 | 8.0 | 1587 | 7.2 |
Previous influenza infection | 2 | 0.1 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 6 | 0.7 | 7 | 0.8 | 1 | 0.0 | 0 | 0.0 | 15 | 1.2 | 0 | 0.0 | 9 | 0.6 | 1 | 0.0 | 41 | 0.2 |
Onset of symptoms to swab > 9 days | 0 | 0.0 | 1 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 2 | 0.2 | 1 | 0.0 | 6 | 5.7 | 1 | 0.1 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 11 | 0.1 |
Sample inadequate | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 |
Sample lost | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 25 | 23.6 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 25 | 0.1 |
Recruited outside periods with continuous influenza positive admissions | 9 | 0.4 | 13 | 0.6 | 100 | 15.1 | 11 | 5.5 | 1 | 0.0 | 0 | 0.0 | 16 | 1.7 | 131 | 1.9 | 18 | 17.0 | 198 | 15.7 | 159 | 22.9 | 98 | 6.6 | 462 | 21.8 | 1216 | 5.5 |
Included with valid laboratory results | 1937 | 96.3 | 1620 | 72.2 | 159 | 24.1 | 111 | 55.2 | 1132 | 46.2 | 387 | 42.9 | 413 | 45.0 | 2125 | 30.7 | 39 | 36.8 | 470 | 37.2 | 493 | 71.1 | 350 | 23.6 | 904 | 42.6 | 10140 | 46.2 |
RT-PCR result | ||||||||||||||||||||||||||||
Influenza negative | 1417 | 73.2 | 869 | 53.6 | 128 | 80.5 | 69 | 62.2 | 414 | 36.6 | 221 | 57.1 | 311 | 75.3 | 1862 | 87.6 | 30 | 76.9 | 433 | 92.1 | 425 | 86.2 | 259 | 74.0 | 807 | 89.3 | 7245 | 71.4 |
Influenza positive | 520 | 26.8 | 751 | 46.4 | 31 | 19.5 | 42 | 37.8 | 718 | 63.4 | 166 | 42.9 | 102 | 24.7 | 263 | 12.4 | 9 | 23.1 | 37 | 7.9 | 68 | 13.8 | 91 | 26.0 | 97 | 10.7 | 2895 | 28.6 |
Subtype and lineage | ||||||||||||||||||||||||||||
A(H1N1)pdm09 | 1 | 0.2 | 0 | 0.0 | 0 | 0.0 | 1 | 2.4 | 3 | 0.3 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 1 | 11.1 | 1 | 2.7 | 11 | 16.2 | 56 | 61.5 | 2 | 2.1 | 76 | 2.6 |
A(H3N2) | 296 | 56.9 | 420 | 55.9 | 15 | 48.4 | 32 | 76.2 | 585 | 51.7 | 39 | 23.5 | 81 | 79.4 | 251 | 95.4 | 6 | 66.7 | 21 | 56.8 | 21 | 30.9 | 12 | 13.2 | 61 | 62.9 | 1840 | 63.6 |
A not subtyped | 34 | 6.5 | 4 | 0.5 | 0 | 0.0 | 2 | 4.8 | 67 | 5.9 | 4 | 2.4 | 3 | 2.9 | 12 | 4.6 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 3 | 3.1 | 129 | 4.5 |
B/Yamagata lineage | 2 | 0.4 | 0 | 0.0 | 0 | 0.0 | 4 | 9.5 | 35 | 3.1 | 0 | 0.0 | 19 | 18.6 | 0 | 0.0 | 2 | 22.2 | 1 | 2.7 | 0 | 0.0 | 15 | 16.5 | 30 | 30.9 | 108 | 3.7 |
B/Victoria lineage | 187 | 36.0 | 299 | 39.8 | 0 | 0.0 | 1 | 2.4 | 4 | 0.4 | 74 | 44.6 | 2 | 2.0 | 0 | 0.0 | 0 | 0.0 | 14 | 37.8 | 37 | 54.4 | 0 | 0.0 | 0 | 0.0 | 618 | 21.3 |
B not subtyped | 0 | 0.0 | 28 | 3.7 | 16 | 51.6 | 2 | 4.8 | 24 | 2.1 | 50 | 30.1 | 1 | 1.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 11 | 12.1 | 3 | 3.1 | 135 | 4.7 |
Characteristic | St. Pet | Moscow | Kazakhstan | Czech Rep. | Canada | Romania | Turkey | Valencia | Tunisia | Suzhou/ Shanghai | India | Mexico | South Africa | Total | ||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
N = 1937 | N = 1620 | N = 159 | N = 111 | N = 1132 | N = 387 | N = 413 | N = 2125 | N = 39 | N = 470 | N = 493 | N = 350 | N = 904 | N = 10,140 | |||||||||||||||
n | % | n | % | n | % | n | % | n | % | n | % | n | % | n | % | n | % | n | % | n | % | n | % | n | % | n | % | |
Age in years, median (range) | 3 (0–87) | 24 (0–91) | 17 (1–76) | 64 (18–90) | 76 (17–105) | 5 (0–63) | 3 (0–95) | 68 (0–102) | 58 (14–84) | 0 (0–13) | 60 (0–99) | 3 (0–96) | 0 (0–91) | 20 (0–105) | ||||||||||||||
Age group | ||||||||||||||||||||||||||||
0–1 y | 684 | 35.3 | 167 | 10.3 | 34 | 21.4 | 0 | 0.0 | 0 | 0.0 | 89 | 23.0 | 179 | 43.3 | 421 | 19.8 | 0 | 0.0 | 334 | 71.1 | 57 | 11.6 | 151 | 43.1 | 576 | 63.7 | 2692 | 27.0 |
2–4 y | 483 | 24.9 | 156 | 9.6 | 33 | 20.8 | 0 | 0.0 | 0 | 0.0 | 87 | 22.5 | 39 | 9.4 | 108 | 5.1 | 0 | 0.0 | 96 | 20.4 | 19 | 3.9 | 50 | 14.3 | 146 | 16.2 | 1217 | 12.2 |
5–17 y | 310 | 16.0 | 182 | 11.2 | 14 | 8.8 | 0 | 0.0 | 1 | 0.1 | 118 | 30.5 | 32 | 7.7 | 54 | 2.5 | 1 | 2.6 | 40 | 8.5 | 16 | 3.2 | 43 | 12.3 | 16 | 1.8 | 827 | 8.3 |
18–49 y | 388 | 20.0 | 1052 | 64.9 | 73 | 45.9 | 37 | 33.3 | 97 | 8.6 | 72 | 18.6 | 14 | 3.4 | 145 | 6.8 | 9 | 23.1 | 0 | 0.0 | 79 | 16.0 | 52 | 14.9 | 82 | 9.1 | 2100 | 21.1 |
50–64 y | 49 | 2.5 | 34 | 2.1 | 2 | 1.3 | 20 | 18.0 | 156 | 13.8 | 21 | 5.4 | 45 | 10.9 | 227 | 10.7 | 12 | 30.8 | 0 | 0.0 | 100 | 20.3 | 21 | 6.0 | 48 | 5.3 | 735 | 7.4 |
65–74 y | 12 | 0.6 | 12 | 0.7 | 2 | 1.3 | 24 | 21.6 | 196 | 17.3 | 0 | 0.0 | 29 | 7.0 | 335 | 15.8 | 8 | 20.5 | 0 | 0.0 | 143 | 29.0 | 11 | 3.1 | 21 | 2.3 | 793 | 8.0 |
75–84 y | 9 | 0.5 | 10 | 0.6 | 1 | 0.6 | 20 | 18.0 | 264 | 23.3 | 0 | 0.0 | 55 | 13.3 | 462 | 21.7 | 9 | 23.1 | 0 | 0.0 | 51 | 10.3 | 11 | 3.1 | 11 | 1.2 | 903 | 9.0 |
≥ 85 y | 2 | 0.1 | 7 | 0.4 | 0 | 0.0 | 10 | 9.0 | 246 | 21.7 | 0 | 0.0 | 20 | 4.8 | 373 | 17.6 | 0 | 0.0 | 0 | 0.0 | 28 | 5.7 | 11 | 3.1 | 4 | 0.4 | 701 | 7.0 |
Sex | ||||||||||||||||||||||||||||
Male | 1050 | 54.2 | 607 | 37.5 | 76 | 47.8 | 64 | 57.7 | 541 | 47.8 | 205 | 53.0 | 224 | 54.2 | 1125 | 52.9 | 27 | 69.2 | 287 | 61.1 | 242 | 49.1 | 171 | 48.9 | 486 | 53.8 | 5105 | 50.3 |
Female | 887 | 45.8 | 1013 | 62.5 | 83 | 52.2 | 47 | 42.3 | 591 | 52.2 | 182 | 47.0 | 189 | 45.8 | 1000 | 47.1 | 12 | 30.8 | 183 | 38.9 | 251 | 50.9 | 179 | 51.1 | 418 | 46.2 | 5035 | 49.7 |
Chronic conditions | ||||||||||||||||||||||||||||
0 | 1758 | 90.8 | 1382 | 85.3 | 111 | 69.8 | 35 | 31.5 | 99 | 8.7 | 349 | 90.2 | 214 | 51.8 | 803 | 37.8 | 7 | 17.9 | 443 | 94.3 | 129 | 26.2 | 218 | 62.3 | 878 | 97.1 | 6426 | 63.4 |
1 | 157 | 8.1 | 187 | 11.5 | 42 | 26.4 | 40 | 36.0 | 307 | 27.1 | 28 | 7.2 | 87 | 21.1 | 626 | 29.5 | 18 | 46.2 | 27 | 5.7 | 182 | 36.9 | 85 | 24.3 | 26 | 2.9 | 1812 | 17.9 |
≥2 | 22 | 1.1 | 51 | 3.1 | 6 | 3.8 | 36 | 32.4 | 726 | 64.1 | 10 | 2.6 | 112 | 27.1 | 696 | 32.8 | 14 | 35.9 | 0 | 0.0 | 182 | 36.9 | 47 | 13.4 | 0 | 0.0 | 1902 | 18.7 |
Previously hospitalised (last 12 months) | ||||||||||||||||||||||||||||
No | 1447 | 74.7 | 1354 | 83.6 | 143 | 89.9 | 80 | 72.1 | – | – | 279 | 72.1 | 272 | 65.9 | 1457 | 68.6 | 30 | 76.9 | 329 | 70.0 | 312 | 63.3 | 240 | 68.6 | 745 | 82.4 | 6688 | 74.2 |
Yes | 490 | 25.3 | 266 | 16.4 | 16 | 10.1 | 31 | 27.9 | – | – | 108 | 27.9 | 141 | 34.1 | 668 | 31.4 | 9 | 23.1 | 141 | 30.0 | 181 | 36.7 | 110 | 31.4 | 159 | 17.6 | 2320 | 25.8 |
Underlying chronic conditions | ||||||||||||||||||||||||||||
Cardiovascular disease | 49 | 2.5 | 70 | 4.3 | 5 | 3.1 | 50 | 45.0 | 872 | 77.0 | 17 | 4.4 | 110 | 26.6 | 602 | 28.3 | 15 | 38.5 | 24 | 5.1 | 199 | 40.4 | 65 | 18.6 | 16 | 1.8 | 2094 | 20.7 |
Chronic obstructive pulmonary disease | 21 | 1.1 | 23 | 1.4 | 24 | 15.1 | 7 | 6.3 | 134 | 11.8 | 1 | 0.3 | 70 | 16.9 | 500 | 23.5 | 21 | 53.8 | 0 | 0.0 | 177 | 35.9 | 28 | 8.0 | 2 | 0.2 | 1008 | 9.9 |
Asthma | 28 | 1.4 | 29 | 1.8 | 0 | 0.0 | 7 | 6.3 | 146 | 12.9 | 2 | 0.5 | 46 | 11.1 | 162 | 7.6 | 2 | 5.1 | 2 | 0.4 | 5 | 1.0 | 27 | 7.7 | 7 | 0.8 | 463 | 4.6 |
Immunodeficiency/organ transplant | 13 | 0.7 | 1 | 0.1 | 1 | 0.6 | 4 | 3.6 | 114 | 10.1 | 8 | 2.1 | 18 | 4.4 | 29 | 1.4 | 1 | 2.6 | 0 | 0.0 | 17 | 3.4 | 16 | 4.6 | 0 | 0.0 | 222 | 2.2 |
Diabetes | 7 | 0.4 | 16 | 1.0 | 3 | 1.9 | 25 | 22.5 | 344 | 30.4 | 6 | 1.6 | 47 | 11.4 | 500 | 23.5 | 7 | 17.9 | 0 | 0.0 | 71 | 14.4 | 23 | 6.6 | 0 | 0.0 | 1049 | 10.3 |
Renal impairment | 4 | 0.2 | 74 | 4.6 | 15 | 9.4 | 3 | 2.7 | 167 | 14.8 | 4 | 1.0 | 27 | 6.5 | 274 | 12.9 | 4 | 10.3 | 1 | 0.2 | 29 | 5.9 | 14 | 4.0 | 1 | 0.1 | 617 | 6.1 |
Neuromuscular disease | 56 | 2.9 | 29 | 1.8 | 6 | 3.8 | 6 | 5.4 | 182 | 16.1 | 0 | 0.0 | 31 | 7.5 | 57 | 2.7 | 1 | 2.6 | 0 | 0.0 | 45 | 9.1 | 13 | 3.7 | 0 | 0.0 | 426 | 4.2 |
Neoplasm | 0 | 0.0 | 15 | 0.9 | 0 | 0.0 | 11 | 9.9 | 239 | 21.1 | 5 | 1.3 | 27 | 6.5 | 141 | 6.6 | 0 | 0.0 | 0 | 0.0 | 33 | 6.7 | 8 | 2.3 | 0 | 0.0 | 479 | 4.7 |
Cirrhosis/liver disease | 18 | 0.9 | 18 | 1.1 | 1 | 0.6 | 3 | 2.7 | 22 | 1.9 | 5 | 1.3 | 6 | 1.5 | 62 | 2.9 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 135 | 1.3 |
Autoimmune disease | 7 | 0.4 | 29 | 1.8 | 0 | 0.0 | 5 | 4.5 | 1 | 0.1 | 5 | 1.3 | 5 | 1.2 | 43 | 2.0 | 2 | 5.1 | 0 | 0.0 | 22 | 4.5 | 12 | 3.4 | 0 | 0.0 | 131 | 1.3 |
Pregnant (women 15–45 y) | 72 | 3.7 | 800 | 49.4 | 36 | 22.6 | 3 | 2.7 | 14 | 1.2 | 7 | 1.8 | 0 | 0.0 | 2 | 0.1 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 2 | 0.6 | 4 | 0.4 | 940 | 9.3 |
Obese (all ages) | 165 | 8.5 | 150 | 9.3 | 13 | 8.2 | 26 | 23.4 | 197 | 29.6 | 35 | 9.0 | 76 | 18.4 | 559 | 26.3 | 5 | 12.8 | 77 | 16.4 | 37 | 7.5 | 46 | 13.1 | 71 | 9.6 | 1457 | 14.4 |
Outpatient consultations last 3 months | ||||||||||||||||||||||||||||
0 | 894 | 46.2 | 658 | 40.6 | 116 | 73.0 | 33 | 29.7 | – | – | 166 | 42.9 | 148 | 35.8 | 233 | 11.0 | 14 | 35.9 | 44 | 9.4 | 120 | 24.3 | 81 | 23.1 | 776 | 85.8 | 3283 | 36.4 |
1 | 624 | 32.2 | 238 | 14.7 | 43 | 27.0 | 34 | 30.6 | – | – | 121 | 31.3 | 100 | 24.2 | 413 | 19.4 | 11 | 28.2 | 123 | 28.3 | 59 | 12.0 | 70 | 20.0 | 82 | 9.1 | 1928 | 21.4 |
≥ 2 | 419 | 21.6 | 724 | 44.7 | 0 | 0.0 | 44 | 39.6 | – | – | 100 | 25.8 | 165 | 40.0 | 1479 | 69.6 | 14 | 35.9 | 293 | 62.3 | 314 | 63.7 | 199 | 56.9 | 46 | 5.1 | 3797 | 42.2 |
Smoking habits (patients ≥18 y) | ||||||||||||||||||||||||||||
Never smoker | 222 | 48.3 | 698 | 62.6 | 58 | 74.4 | 51 | 45.9 | 431 | 43.5 | 55 | 59.1 | 85 | 52.1 | 784 | 50.8 | 15 | 39.5 | 0 | – | 198 | 49.4 | 57 | 53.8 | 102 | 61.4 | 2756 | 52.4 |
Past smoker | 46 | 10.0 | 263 | 23.6 | 16 | 20.5 | 24 | 21.6 | 387 | 39.1 | 6 | 6.5 | 59 | 36.2 | 464 | 30.1 | 12 | 31.6 | 0 | – | 121 | 30.2 | 34 | 32.1 | 35 | 21.1 | 1467 | 27.9 |
Current smoker | 192 | 41.7 | 154 | 13.8 | 4 | 5.1 | 36 | 32.4 | 172 | 17.4 | 32 | 34.4 | 19 | 11.7 | 294 | 19.1 | 11 | 28.9 | 0 | – | 82 | 20.4 | 15 | 14.2 | 29 | 17.5 | 1040 | 19.7 |
Functional status impairment (Barthel score; patients ≥65 y) | ||||||||||||||||||||||||||||
Total (0–15) | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 14 | 2.8 | 0 | – | 8 | 8.3 | 94 | 8.0 | 0 | 0.0 | 0 | – | 13 | 5.9 | 0 | 0.0 | 1 | 5.6 | 130 | 6.0 |
Severe (20–35) | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 11 | 2.2 | 0 | – | 3 | 3.1 | 26 | 2.2 | 3 | 17.6 | 0 | – | 3 | 1.4 | 3 | 9.1 | 1 | 5.6 | 50 | 2.3 |
Moderate (40–55) | 0 | 0.0 | 2 | 6.9 | 0 | 0.0 | 1 | 1.9 | 15 | 3.0 | 0 | – | 3 | 3.1 | 54 | 4.6 | 8 | 47.1 | 0 | – | 8 | 3.6 | 1 | 3.0 | 1 | 5.6 | 93 | 4.3 |
Mild (60–90) | 4 | 18.2 | 7 | 24.1 | 2 | 66.7 | 14 | 25.9 | 90 | 17.9 | 0 | – | 35 | 36.5 | 261 | 22.3 | 4 | 23.5 | 0 | – | 62 | 27.9 | 12 | 36.4 | 9 | 50.0 | 500 | 23.1 |
Minimal (95–100) | 18 | 81.8 | 20 | 69.0 | 1 | 33.3 | 39 | 72.2 | 373 | 74.2 | 0 | – | 47 | 49.0 | 735 | 62.8 | 2 | 11.8 | 0 | – | 136 | 61.3 | 17 | 51.5 | 6 | 33.3 | 1394 | 64.3 |
Sampling time | ||||||||||||||||||||||||||||
0–2 days | 1160 | 59.9 | 843 | 52.0 | 109 | 68.6 | 31 | 27.9 | 474 | 41.9 | 76 | 19.6 | 59 | 14.3 | 386 | 18.2 | 7 | 17.9 | 8 | 1.7 | 44 | 8.9 | 67 | 19.1 | 321 | 39.1 | 3585 | 35.6 |
3–4 days | 568 | 29.3 | 595 | 36.7 | 46 | 28.9 | 42 | 37.8 | 387 | 34.2 | 155 | 40.1 | 161 | 39.0 | 892 | 42.0 | 14 | 35.9 | 107 | 22.8 | 175 | 35.5 | 123 | 35.1 | 308 | 37.5 | 3573 | 35.5 |
5–7 days | 209 | 10.8 | 179 | 11.0 | 4 | 2.5 | 37 | 33.3 | 259 | 22.9 | 144 | 37.2 | 181 | 43.8 | 655 | 30.8 | 18 | 46.2 | 264 | 56.2 | 274 | 55.6 | 141 | 40.3 | 140 | 17.1 | 2505 | 24.9 |
8–9 days | 0 | 0.0 | 3 | 0.2 | 0 | 0.0 | 1 | 0.9 | 12 | 1.1 | 12 | 3.1 | 12 | 2.9 | 192 | 9.0 | 0 | 0.0 | 91 | 19.4 | 0 | 0.0 | 19 | 5.4 | 52 | 6.3 | 394 | 3.9 |
Influenza vaccination ≥15 days from symptom onset | 86 | 4.4 | 65 | 4.0 | 0 | 0.0 | 6 | 5.4 | 139 | 12.3 | 7 | 1.8 | 21 | 5.1 | 825 | 38.8 | 2 | 5.1 | 1 | 0.2 | 11 | 2.2 | 49 | 14.0 | 5 | 0.6 | 1217 | 12.0 |
Influenza vaccination ≥15 days from symptom onset (age ≥ 65) | 2 | 8.7 | 5 | 17.2 | 0 | 0.0 | 6 | 11.1 | 124 | 14.1 | 0 | – | 14 | 13.5 | 701 | 59.9 | 2 | 11.8 | 0 | – | 5 | 2.3 | 9 | 27.3 | 0 | 0.0 | 868 | 33.8 |
Influenza vaccination ≥15 days from symptom onset (targeted groups) | 65 | 4.5 | 30 | 2.2 | 0 | 0.0 | 6 | 7.0 | 138 | 12.7 | 3 | 4.4 | 21 | 9.0 | 806 | 50.3 | 2 | 6.1 | 1 | 0.4 | 8 | 2.1 | 43 | 16.0 | 2 | 1.5 | 1125 | 16.0 |
Influenza negative | Influenza positive | A (H1N1)pdm09 | A (H3N2) | A not subtyped | B/Yamagata | B/Victoria | B not subtyped | ||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
N = 7245 | N = 2895 | N = 76 | N = 1840 | N = 129 | N = 108 | N = 618 | N = 135 | ||||||||||||||||
Characteristic | n | % | n | % | P vs. negative | n | % | P vs. negative | n | % | P vs. negative | n | % | P vs. negative | n | % | P vs. negative | n | % | P vs. negative | n | % | P vs. negative |
Age in years, median (range) | 12 (0–105) | 28 (0–103) | < 0.001 | 35 (0–84) | 0.083 | 35 (0–103) | < 0.001 | 48 (0–102) | < 0.001 | 13 (0–92) | 0.840 | 18 (0–89) | 0.008 | 7 (0–94) | 0.139 | ||||||||
Age group | < 0.0001 | 0.0001 | < 0.0001 | < 0.0001 | 0.0003 | < 0.0001 | < 0.0001 | ||||||||||||||||
0–1 y | 2361 | 32.8 | 331 | 11.9 | 11 | 14.5 | 220 | 12.5 | 16 | 16.0 | 20 | 19.8 | 47 | 7.6 | 20 | 14.9 | |||||||
2–4 y | 906 | 12.6 | 311 | 11.2 | 12 | 15.8 | 162 | 9.2 | 13 | 13.0 | 16 | 15.8 | 86 | 13.9 | 24 | 17.9 | |||||||
5–17 y | 446 | 6.2 | 381 | 13.7 | 7 | 9.2 | 143 | 8.1 | 7 | 7.0 | 15 | 14.9 | 176 | 28.5 | 35 | 26.1 | |||||||
18–49 y | 1305 | 18.1 | 795 | 28.7 | 23 | 30.3 | 440 | 25.1 | 15 | 15.0 | 10 | 9.9 | 282 | 45.6 | 26 | 19.4 | |||||||
50–64 y | 540 | 7.5 | 195 | 7.0 | 13 | 17.1 | 159 | 9.1 | 3 | 3.0 | 12 | 11.9 | 5 | 0.8 | 4 | 3.0 | |||||||
65–74 y | 565 | 7.9 | 228 | 8.2 | 7 | 9.2 | 178 | 10.1 | 15 | 15.0 | 7 | 6.9 | 11 | 1.8 | 10 | 7.5 | |||||||
75–84 y | 631 | 8.8 | 272 | 9.8 | 3 | 3.9 | 223 | 12.7 | 16 | 16.0 | 11 | 10.9 | 9 | 1.5 | 12 | 9.0 | |||||||
≥ 85 y | 441 | 6.1 | 260 | 9.4 | 0 | 0.0 | 230 | 13.1 | 15 | 15.0 | 10 | 9.9 | 2 | 0.3 | 3 | 2.2 | |||||||
Sex | < 0.0001 | 0.1374 | < 0.0001 | 0.3877 | 0.6826 | < 0.0001 | 0.5137 | ||||||||||||||||
Male | 3766 | 52.0 | 1339 | 46.3 | 33 | 43.4 | 859 | 46.7 | 72 | 55.8 | 54 | 50.0 | 254 | 41.1 | 74 | 54.8 | |||||||
Female | 3479 | 48.0 | 1556 | 53.7 | 43 | 56.6 | 981 | 53.3 | 57 | 44.2 | 54 | 50.0 | 364 | 58.9 | 61 | 45.2 | |||||||
Chronic conditions | < 0.0001 | 0.1801 | < 0.0001 | < 0.0001 | 0.0025 | < 0.0001 | 0.6485 | ||||||||||||||||
0 | 4765 | 65.8 | 1661 | 57.4 | 44 | 57.9 | 894 | 48.6 | 51 | 39.5 | 58 | 53.7 | 528 | 85.4 | 92 | 68.1 | |||||||
1 | 1240 | 17.1 | 572 | 19.8 | 19 | 25.0 | 415 | 22.6 | 27 | 20.9 | 18 | 16.7 | 71 | 11.5 | 24 | 17.8 | |||||||
≥2 | 1240 | 17.1 | 662 | 22.9 | 13 | 17.1 | 531 | 28.9 | 51 | 39.5 | 32 | 29.6 | 19 | 3.1 | 19 | 14.1 | |||||||
Previously hospitalised (last 12 months) | 0.0163 | 0.2604 | 0.9969 | 0.6372 | 0.8445 | 0.0002 | 0.0086 | ||||||||||||||||
No | 5029 | 73.6 | 1659 | 76.2 | 58 | 79.5 | 924 | 73.6 | 44 | 71.0 | 53 | 72.6 | 494 | 80.5 | 94 | 84.7 | |||||||
Yes | 1802 | 26.4 | 518 | 23.8 | 15 | 20.5 | 331 | 26.4 | 18 | 29.0 | 20 | 27.4 | 120 | 19.5 | 17 | 15.3 | |||||||
Underlying chronic conditions | |||||||||||||||||||||||
Cardiovascular disease | 1298 | 17.9 | 796 | 27.5 | < 0.0001 | 17 | 22.4 | 0.3145 | 627 | 34.1 | < 0.0001 | 60 | 46.5 | < 0.0001 | 37 | 34.3 | < 0.0001 | 30 | 4.9 | < 0.0001 | 28 | 20.7 | 0.3970 |
Chronic obstructive pulmonary disease | 802 | 11.1 | 206 | 7.1 | < 0.0001 | 8 | 10.5 | 0.8806 | 159 | 8.6 | 0.0025 | 10 | 7.8 | 0.2328 | 10 | 9.3 | 0.5513 | 16 | 2.6 | < 0.0001 | 7 | 5.2 | 0.0301 |
Asthma | 276 | 3.8 | 187 | 6.5 | < 0.0001 | 6 | 7.9 | 0.0656 | 147 | 8.0 | < 0.0001 | 14 | 10.9 | < 0.0001 | 8 | 7.4 | 0.0541 | 8 | 1.3 | 0.0013 | 4 | 3.0 | 0.6100 |
Immunodeficiency/organ transplant | 155 | 2.1 | 67 | 2.3 | 0.5867 | 3 | 3.9 | 0.2806 | 49 | 2.7 | 0.1758 | 7 | 5.4 | 0.0116 | 3 | 2.8 | 0.6497 | 2 | 0.3 | 0.0020 | 3 | 2.2 | 0.9475 |
Diabetes | 687 | 9.5 | 362 | 12.5 | < 0.0001 | 11 | 14.5 | 0.1405 | 292 | 15.9 | < 0.0001 | 33 | 25.6 | < 0.0001 | 13 | 12.0 | 0.3693 | 5 | 0.8 | < 0.0001 | 8 | 5.9 | 0.1610 |
Renal impairment | 409 | 5.6 | 208 | 7.2 | 0.0034 | 4 | 5.3 | 0.8858 | 161 | 8.8 | < 0.0001 | 11 | 8.5 | 0.1616 | 7 | 6.5 | 0.7089 | 19 | 3.1 | 0.0069 | 7 | 5.2 | 0.8184 |
Neuromuscular disease | 234 | 3.2 | 192 | 6.6 | < 0.0001 | 2 | 2.6 | 0.7690 | 147 | 8.0 | < 0.0001 | 15 | 11.6 | < 0.0001 | 8 | 7.4 | 0.0157 | 12 | 1.9 | 0.0775 | 9 | 6.7 | 0.0266 |
Neoplasm | 311 | 4.3 | 168 | 5.8 | 0.0012 | 0 | 0.0 | 0.0649 | 133 | 7.2 | < 0.0001 | 20 | 15.5 | < 0.0001 | 7 | 6.5 | 0.2670 | 4 | 0.6 | < 0.0001 | 5 | 3.7 | 0.7377 |
Cirrhosis/liver disease | 97 | 1.3 | 38 | 1.3 | 0.9171 | 0 | 0.0 | 0.3099 | 29 | 1.6 | 0.4372 | 3 | 2.3 | 0.3369 | 1 | 0.9 | 0.7103 | 4 | 0.6 | 0.1428 | 1 | 0.7 | 0.5475 |
Autoimmune disease | 96 | 1.3 | 35 | 1.2 | 0.6402 | 1 | 1.3 | 0.9944 | 16 | 0.9 | 0.1139 | 1 | 0.8 | 0.5869 | 4 | 3.7 | 0.0341 | 12 | 1.9 | 0.2061 | 1 | 0.7 | 0.5548 |
Pregnant (women 15–45 y) | 459 | 58.0 | 481 | 82.7 | < 0.0001 | 1 | 10.0 | 0.0023 | 272 | 83.7 | < 0.0001 | 2 | 28.6 | 0.1164 | 1 | 14.3 | 0.0198 | 196 | 89.9 | < 0.0001 | 9 | 56.3 | 0.8866 |
Obese (all ages) | 1083 | 15.6 | 374 | 14.6 | 0.1967 | 18 | 25.4 | 0.0250 | 271 | 17.0 | 0.1905 | 13 | 17.1 | 0.7231 | 17 | 18.3 | 0.4834 | 46 | 7.4 | < 0.0001 | 12 | 9.6 | 0.0654 |
Outpatient consultations last 3 months | 0.6362 | 0.7448 | 0.0005 | 0.7360 | 0.0061 | 0.0120 | 0.0008 | ||||||||||||||||
0 | 2504 | 36.7 | 779 | 35.8 | 25 | 34.2 | 388 | 30.9 | 20 | 32.3 | 40 | 54.8 | 262 | 42.7 | 48 | 43.2 | |||||||
1 | 1448 | 21.2 | 480 | 22.0 | 14 | 19.2 | 287 | 22.9 | 15 | 24.2 | 11 | 15.1 | 121 | 19.7 | 35 | 31.5 | |||||||
≥ 2 | 2879 | 42.1 | 918 | 42.2 | 34 | 46.6 | 580 | 46.2 | 27 | 43.5 | 22 | 30.1 | 231 | 37.6 | 28 | 25.2 | |||||||
Smoking habits (patients ≥18 y) | < 0.0001 | 0.0753 | < 0.0001 | 0.1387 | 0.9041 | 0.1663 | 0.0818 | ||||||||||||||||
Never smoker | 4106 | 57.0 | 1598 | 57.5 | 42 | 56.0 | 993 | 56.7 | 62 | 53.9 | 57 | 56.4 | 367 | 59.5 | 84 | 64.1 | |||||||
Past smoker | 1366 | 19.0 | 640 | 23.0 | 21 | 28.0 | 459 | 26.2 | 23 | 20.0 | 18 | 17.8 | 98 | 15.9 | 15 | 11.5 | |||||||
Current smoker | 1728 | 24.0 | 542 | 19.5 | 12 | 16.0 | 300 | 17.1 | 30 | 26.1 | 26 | 25.7 | 152 | 24.6 | 32 | 24.4 | |||||||
Functional status impairment (Barthel score; patients ≥65 y) | 0.0764 | 0.5686 | 0.1750 | 0.9911 | 0.4228 | 0.6788 | 0.0012 | ||||||||||||||||
Total (0–15) | 106 | 6.8 | 24 | 3.9 | 0 | 0.0 | 21 | 4.2 | 3 | 7.3 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | |||||||
Severe (20–35) | 35 | 2.3 | 15 | 2.4 | 0 | 0.0 | 11 | 2.2 | 1 | 2.4 | 0 | 0.0 | 0 | 0.0 | 3 | 13.0 | |||||||
Moderate (40–55) | 62 | 4.0 | 31 | 5.0 | 0 | 0.0 | 26 | 5.2 | 1 | 2.4 | 0 | 0.0 | 1 | 4.5 | 3 | 13.0 | |||||||
Mild (60–90) | 364 | 23.5 | 136 | 22.1 | 4 | 44.4 | 109 | 21.9 | 10 | 24.4 | 6 | 24.0 | 5 | 22.7 | 3 | 13.0 | |||||||
Minimal (95–100) | 985 | 63.5 | 409 | 66.5 | 5 | 55.6 | 330 | 66.4 | 26 | 63.4 | 19 | 76.0 | 16 | 72.7 | 14 | 60.9 | |||||||
Sampling time | < 0.0001 | 0.0051 | < 0.0001 | 0.0797 | 0.7704 | < 0.0001 | 0.3919 | ||||||||||||||||
0–2 days | 2374 | 33.1 | 1211 | 42.0 | 16 | 21.1 | 830 | 45.3 | 54 | 41.9 | 35 | 32.7 | 237 | 38.3 | 40 | 29.6 | |||||||
3–4 days | 2521 | 35.2 | 1052 | 36.5 | 22 | 28.9 | 657 | 35.9 | 38 | 29.5 | 41 | 38.3 | 244 | 39.5 | 53 | 39.3 | |||||||
5–7 days | 1941 | 27.1 | 564 | 19.5 | 34 | 44.7 | 303 | 16.5 | 35 | 27.1 | 28 | 26.2 | 132 | 21.4 | 39 | 28.9 | |||||||
8–9 days | 335 | 4.7 | 59 | 2.0 | 4 | 5.3 | 42 | 2.3 | 2 | 1.6 | 3 | 2.8 | 5 | 0.8 | 3 | 2.2 | |||||||
Influenza vaccination ≥15 days from symptom onset | 938 | 13.0 | 279 | 9.6 | < 0.0001 | 7 | 9.2 | 0.3339 | 221 | 12.0 | 0.2825 | 10 | 7.8 | 0.0806 | 9 | 8.3 | 0.1554 | 25 | 4.1 | < 0.0001 | 8 | 5.9 | 0.0156 |
Influenza vaccination ≥15 days from symptom onset (age ≥ 65) | 673 | 39.9 | 195 | 22.1 | < 0.0001 | 1 | 10.0 | 0.0541 | 175 | 24.4 | < 0.0001 | 8 | 10.7 | < 0.0001 | 6 | 17.1 | 0.0064 | 1 | 4.6 | 0.0008 | 4 | 15.4 | 0.0112 |
Influenza vaccination ≥15 days from symptom onset (targeted groups) | 869 | 18.4 | 256 | 11.1 | < 0.0001 | 7 | 13.0 | 0.3047 | 214 | 13.6 | < 0.0001 | 8 | 7.2 | 0.0025 | 7 | 11.1 | 0.1373 | 14 | 3.1 | < 0.0001 | 7 | 9.7 | 0.0586 |
All admissions | Influenza-positive | Crude OR | Heterogeneity by strain (I2) | aOR(*) | ||||
---|---|---|---|---|---|---|---|---|
N = 10140 | N = 2895 | |||||||
Characteristic | N | N | % | Value | 95% CI | Value | 95% CI | |
Age group | ||||||||
0–1 years | 2692 | 331 | 12.3 | 1.00 | – | 79.4% | 1.00 | – |
2–4 years | 1217 | 311 | 25.6 | 2.45 | 2.06–2.92 | 75.6% | 0.86 | 0.67–1.09 |
5–17 years | 827 | 381 | 46.1 | 6.09 | 5.03–7.38 | 94.6% | 1.59 | 0.85–2.96 |
18–49 years | 2100 | 795 | 37.9 | 4.35 | 3.73–5.06 | 96.4% | 0.65 | 0.22–1.97 |
50–64 years | 735 | 195 | 26.5 | 2.58 | 2.10–3.15 | 96.6% | 0.59 | 0.25–1.39 |
65–74 years | 793 | 228 | 28.8 | 2.88 | 2.37–3.50 | 95.3% | 0.61 | 0.31–1.22 |
75–84 years | 903 | 272 | 30.1 | 3.07 | 2.55–3.71 | 96.9% | 0.50 | 0.21–1.20 |
≥ 85 years | 701 | 260 | 37.1 | 4.21 | 3.45–5.13 | 98.4% | 0.49 | 0.19–1.28 |
Sex | ||||||||
Male | 5105 | 1339 | 26,2% | 1.00 | 54.0% | 1.00 | ||
Female | 5035 | 1556 | 30,9% | 1.26 | 1.15–1.37 | 46.5% | 0.84 | 0.74–0.95 |
Smoking habits | ||||||||
Current smoker | 2270 | 542 | 23,9% | 1.00 | 81.7% | 1.00 | ||
Past smoker | 2006 | 640 | 31,9% | 1.49 | 1.30–1.71 | 88.4% | 1.04 | 0.89–1.22 |
Never smoker | 5704 | 1598 | 28,0% | 1.24 | 1.11–1.39 | 34.0% | 1.09 | 0.93–1.28 |
Consultations at the GP (last 3 months) | ||||||||
No | 3283 | 779 | 23,7% | 1.00 | 95.0% | 1.00 | ||
Yes | 5725 | 1398 | 24,4% | 1.04 | 0.94–1.15 | 92.6% | 0.91 | 0.69–1.18 |
Occupation / Social class | ||||||||
Qualified | 3810 | 1255 | 32,9% | 1.00 | 97.1% | 1.00 | ||
Skilled | 1376 | 355 | 25,8% | 0.71 | 0.62–0.81 | 81.9% | 0.83 | 0.72–0.94 |
Low or unskilled | 3411 | 591 | 17,3% | 0.43 | 0.38–0.48 | 91.5% | 0.63 | 0.50–0.78 |
Other risk factors | ||||||||
Comorbidity | 3714 | 1234 | 33,2% | 1.43 | 1.31–1.56 | 98.7% | 0.90 | 0.63–1.30 |
Cardiovascular disease | 2094 | 796 | 38,0% | 1.74 | 1.57–1.92 | 98.7% | 1.01 | 0.72–1.40 |
Chronic obstructive pulmonary disease | 1008 | 206 | 20,4% | 0.62 | 0.52–0.72 | 92.5% | 0.66 | 0.45–0.98 |
Asthma | 463 | 187 | 40,4% | 1.74 | 1.44–2.11 | 94.3% | 1.31 | 0.96–1.77 |
Immunodeficiency/organ transplant | 222 | 67 | 30,2% | 1.08 | 0.81–1.45 | 85.2% | 0.57 | 0.28–1.17 |
Diabetes | 1049 | 362 | 34,5% | 1.36 | 1.19–1.56 | 98.1% | 1.19 | 1.03–1.37 |
Chronic renal impairment | 617 | 208 | 33,7% | 1.29 | 1.09–1.54 | 89.2% | 1.06 | 0.89–1.27 |
Chronic neuromuscular disease | 426 | 192 | 45,1% | 2.13 | 1.75–2.59 | 91.7% | 1.08 | 0.75–1.56 |
Active neoplasm | 479 | 168 | 35,1% | 1.37 | 1.13–1.67 | 96.8% | 0.63 | 0.42–0.95 |
Chronic liver disease | 135 | 38 | 28,1% | 0.98 | 0.67–1.43 | 38.8% | 1.09 | 0.79–1.50 |
Autoimmune disease | 131 | 35 | 26,7% | 0.91 | 0.62–1.35 | 23.8% | 1.14 | 0.84–1.56 |
Obesity | 1457 | 374 | 25,7% | 0.92 | 0.81–1.04 | 93.3% | 0.83 | 0.69–1.00 |
Pregnancy | 942 | 483 | 51,3% | 2.96 | 2.58–3.40 | 97.6% | 3.02 | 1.59–5.76 |
Days from onset of symptoms to swabbing | ||||||||
0–2 days | 3585 | 1211 | 33,8% | 1.00 | 92.8% | 1.00 | ||
3–4 days | 3573 | 1052 | 29,4% | 0.82 | 0.74–0.90 | 36.9% | 1.05 | 0.99–1.12 |
5–7 days | 2505 | 564 | 22,5% | 0.57 | 0.51–0.64 | 83.4% | 0.82 | 0.64–1.07 |
8–9 days | 394 | 59 | 15,0% | 0.35 | 0.26–0.46 | 65.2% | 0.60 | 0.47–0.77 |
Influenza-negative | Influenza-positive | A(H1N1)pdm09 | A (H3N2) | A not subtyped | B/Yamagata | B/Victoria | B not subtyped | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
N=7245 | N=2895 | N=76 | N=1840 | N=129 | N=108 | N=618 | N=135 | |||||||||||
Category | n | % | n | % | P vs. negative | n | % | n | % | n | % | n | % | n | % | n | % | P-value for distribution by strain |
Severity indicator | ||||||||||||||||||
Intensive care unit admission | 317 | 4.4 | 132 | 4.6 | 0.6656 | 9 | 11.8 | 102 | 5.5 | 5 | 3.9 | 5 | 4.6 | 6 | 1.0 | 6 | 4.4 | <0.0001 |
Mechanical ventilation | 225 | 3.1 | 75 | 2.6 | 0.1728 | 5 | 6.6 | 61 | 3.3 | 3 | 2.3 | 2 | 1.9 | 3 | 0.5 | 2 | 1.5 | 0.0018 |
Extracorporeal membrane oxygenation | 89 | 1.2 | 9 | 0.3 | 0.0000 | 0 | 0.0 | 5 | 0.3 | 3 | 2.3 | 0 | 0.0 | 1 | 0.2 | 0 | 0.0 | 0.0035 |
Death during hospitalisation | 183 | 2.5 | 69 | 2.4 | 0.6904 | 4 | 5.3 | 52 | 2.8 | 3 | 2.3 | 3 | 2.8 | 5 | 0.8 | 2 | 1.5 | 0.0745 |
Length of stay (days), median (interquartile range) | 6 | (3-8) | 5 | (3-8) | <0.001 | 6 | (3-10) | 5 | (3-8) | 6 | (3-9) | 4 | (2-6.5) | 6 | (4-8) | 5 | (3-7) | 0.004 |
Respiratory diagnoses | <0.0001 | 0.3163 | ||||||||||||||||
None | 2052 | 28.3 | 1828 | 63.1 | 15 | 19.7 | 1191 | 64.7 | 79 | 61.2 | 51 | 47.2 | 435 | 70.4 | 60 | 44.4 | ||
Pneumonia | 2335 | 32.2 | 658 | 22.7 | 58 | 76.3 | 362 | 19.7 | 37 | 28.7 | 40 | 37.0 | 112 | 18.1 | 55 | 40.7 | ||
COPD exacerbation | 192 | 2.7 | 91 | 3.1 | 2 | 2.6 | 74 | 4.0 | 5 | 3.9 | 3 | 2.8 | 3 | 0.5 | 4 | 3.0 | ||
Respiratory failure | 109 | 1.5 | 12 | 0.4 | 1 | 1.3 | 9 | 0.5 | 1 | 0.8 | 0 | 0.0 | 0 | 0.0 | 1 | 0.7 | ||
Asthma exacerbation | 53 | 0.7 | 30 | 1.0 | 0 | 0.0 | 29 | 1.6 | 0 | 0.0 | 0 | 0.0 | 1 | 0.2 | 0 | 0.0 | ||
Acute respiratory distress syndrome | 18 | 0.2 | 2 | 0.1 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 2 | 0.3 | 0 | 0.0 | ||
Pneumotorax | 1 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | ||
Bronchiolitis | 383 | 5.3 | 48 | 1.7 | 0 | 0.0 | 29 | 1.6 | 1 | 0.8 | 0 | 0.0 | 12 | 1.9 | 6 | 4.4 | ||
Upper respiratory infection | 2101 | 29.0 | 226 | 7.8 | 0 | 0.0 | 146 | 7.9 | 6 | 4.7 | 14 | 13.0 | 53 | 8.6 | 9 | 6.7 | ||
Metabolic failure | 0.1725 | 0.2106 | ||||||||||||||||
No | 7016 | 96.8 | 2827 | 97.7 | 72 | 94.7 | 1803 | 98.0 | 126 | 97.7 | 106 | 98.1 | 604 | 97.7 | 127 | 94.1 | ||
Acute renal failure | 85 | 1.2 | 19 | 0.7 | 3 | 3.9 | 10 | 0.5 | 2 | 1.6 | 2 | 1.9 | 0 | 0.0 | 2 | 1.5 | ||
Diabetic coma | 8 | 0.1 | 1 | 0.0 | 0 | 0.0 | 1 | 0.1 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | ||
Fluid/electrolyte/acid-base/balance disorders | 136 | 1.9 | 48 | 1.7 | 1 | 1.3 | 26 | 1.4 | 1 | 0.8 | 0 | 0.0 | 14 | 2.3 | 6 | 4.4 | ||
Cardiovascular events | <0.0001 | <0.0001 | ||||||||||||||||
None | 6674 | 92.1 | 2766 | 95.5 | 69 | 90.8 | 1741 | 94.6 | 122 | 94.6 | 104 | 96.3 | 611 | 98.9 | 129 | 95.6 | ||
Acute myocardial infarction | 6 | 0.1 | 1 | 0.0 | 0 | 0.0 | 1 | 0.1 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | ||
Arterial or venous embolia | 1 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | ||
Carditis | 2 | 0.0 | 1 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 1 | 0.2 | 0 | 0.0 | ||
Cardiac arrest | 1 | 0.0 | 1 | 0.0 | 0 | 0.0 | 1 | 0.1 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | ||
Malignant hypertension | 1 | 0.0 | 3 | 0.1 | 0 | 0.0 | 2 | 0.1 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 1 | 0.7 | ||
Any cardiovascular condition | 560 | 7.7 | 123 | 4.2 | 7 | 9.2 | 95 | 5.2 | 7 | 5.4 | 4 | 3.7 | 6 | 1.0 | 5 | 3.7 | ||
Neurologic events | 0.4268 | 0.4345 | ||||||||||||||||
No | 7241 | 99.9 | 2894 | 100.0 | 76 | 100.0 | 1839 | 99.9 | 129 | 100.0 | 108 | 100.0 | 618 | 100.0 | 135 | 100.0 | ||
Altered mental status | 3 | 0.0 | 1 | 0.0 | 0 | 0.0 | 1 | 0.1 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | ||
Convulsions | 1 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | ||
Major discharge diagnoses | <0.0001 | <0.0001 | ||||||||||||||||
Influenza | 241 | 3.3 | 2272 | 78.5 | 40 | 52.6 | 1401 | 76.1 | 97 | 75.2 | 39 | 36.1 | 584 | 94.5 | 113 | 83.7 | ||
Pneumonia | 2427 | 33.5 | 238 | 8.2 | 31 | 40.8 | 145 | 7.9 | 12 | 9.3 | 29 | 26.9 | 13 | 2.1 | 12 | 8.9 | ||
Other respiratory disease | 2683 | 37.0 | 177 | 6.1 | 1 | 1.3 | 132 | 7.2 | 8 | 6.2 | 15 | 13.9 | 17 | 2.8 | 6 | 4.4 | ||
Cardiovascular | 267 | 3.7 | 34 | 1.2 | 1 | 1.3 | 31 | 1.7 | 1 | 0.8 | 1 | 0.9 | 0 | 0.0 | 1 | 0.7 | ||
Other | 1627 | 22.5 | 174 | 6.0 | 3 | 3.9 | 131 | 7.1 | 11 | 8.5 | 24 | 22.2 | 4 | 0.6 | 3 | 2.2 |
Risk variables | Unvaccinated | Vaccinated | P value | |||
---|---|---|---|---|---|---|
Category | n | % | n | % | ||
Number of patients, n (%) | Controls | 6307 | 70.7 | 938 | 77.1 | < 0.0001 |
Cases | 2616 | 29.3 | 279 | 22.9 | ||
Age (y) | Median (range) | 11.4 (0–105.3) | 76.5 (0.6–102.8) | < 0.0001 | ||
Age group, n (%) (2) | 0–5 months | 1254 | 14.3% | 0 | 0.0% | < 0.0001 |
6–11 months | 643 | 7.3% | 13 | 1.1% | ||
1–4 yrs | 1948 | 22.2% | 51 | 4.3% | ||
5–17 yrs | 760 | 8.7% | 67 | 5.6% | ||
18–49 yrs | 1988 | 22.7% | 112 | 9.4% | ||
50–64 yrs | 628 | 7.2% | 106 | 8.9% | ||
65–74 yrs | 583 | 6.6% | 210 | 17.6% | ||
75–84 yrs | 566 | 6.5% | 337 | 28.2% | ||
≥85 y | 403 | 4.6% | 299 | 25.0% | ||
Sex, n (%) | Male | 4462 | 50.0% | 643 | 52.8% | 0.0641 |
Female | 4461 | 50.0% | 574 | 47.2% | ||
Comorbidities, n (%) | None | 6123 | 68.6% | 303 | 24.9% | < 0.0001 |
1 | 1457 | 16.3% | 355 | 29.2% | ||
> 1 | 1343 | 15.1% | 559 | 45.9% | ||
Pregnant, n (%) | – | 921 | 69.5% | 19 | 40.4% | < 0.0001 |
Obesity, n (%) | – | 1148 | 13.8% | 309 | 26.7% | < 0.0001 |
Previous hospitalisation within 12 months, n (%) | – | 1914 | 24.1% | 406 | 37.7% | < 0.0001 |
GP visit within 3 months, n (%) | None | 3074 | 38.8% | 209 | 19.4% | < 0.0001 |
1 | 1740 | 21.9% | 188 | 17.4% | ||
> 1 | 3116 | 39.3% | 681 | 63.2% | ||
Smoking, n (%) | Current | 2112 | 24.1% | 158 | 13.0% | < 0.0001 |
Past | 1618 | 18.5% | 388 | 32.0% | ||
Never | 5037 | 57.5% | 667 | 55.0% | ||
Functional impairment in ≥65 y, n (%) | None or minimal | 72 | 5.4% | 58 | 7.0% | 0.4086 |
Mild | 32 | 2.4% | 18 | 2.2% | ||
Moderate | 52 | 3.9% | 41 | 4.9% | ||
Severe | 309 | 23.1% | 191 | 23.0% | ||
Total | 871 | 65.2% | 523 | 62.9% | ||
Sampling interval (days) | Median (range) | 3 (0–9) | 4 (0–9) | < 0.0001 | ||
Sampling interval, n (%) | ≤4 days | 6377 | 72.1% | 781 | 64.2% | < 0.0001 |
5–7 days | 2148 | 24.3% | 357 | 29.3% | ||
8–9 days | 315 | 3.6% | 79 | 6.5% | ||
Site, n (%) | St. Pet | 1851 | 20.7% | 86 | 7.1% | < 0.0001 |
Moscow | 1555 | 17.4% | 65 | 5.3% | ||
Kazakhstan | 159 | 1.8% | 0 | 0.0% | ||
Czech Republic | 105 | 1.2% | 6 | 0.5% | ||
Canada | 993 | 11.1% | 139 | 11.4% | ||
Romania | 380 | 4.3% | 7 | 0.6% | ||
Turkey | 392 | 4.4% | 21 | 1.7% | ||
Valencia | 1300 | 14.6% | 825 | 67.8% | ||
Tunisia | 37 | 0.4% | 2 | 0.2% | ||
Suzhou/Shanghai | 469 | 5.3% | 1 | 0.1% | ||
India | 482 | 5.4% | 11 | 0.9% | ||
Mexico | 301 | 3.4% | 49 | 4.0% | ||
South Africa | 899 | 10.1% | 5 | 0.4% | ||
Vaccinated, n (%) | In 2015–2016 | 718 | 8.0% | 949 | 78.0% | < 0.0001 |
In 2014–2015 | 589 | 6.6% | 818 | 67.2% | < 0.0001 |
IVE estimates for included patients
Influenza-positive | Influenza-negative | Adjusted IVE(*) | ||||||
---|---|---|---|---|---|---|---|---|
Population | Strain | Age | Total | Vaccinated | Total | Vaccinated | Percent (95% CI) | P-value |
Overall | Any | Any | 2895 | 279 | 7245 | 938 | 27 (15, 38) | |
<65 y | 2013 | 84 | 5558 | 265 | 27 (−1, 48) | 0.804 | ||
≥65 y | 882 | 195 | 1687 | 673 | 25 (3, 43) | |||
A (H1N1) pdm09 | Any | 76 | 7 | 7245 | 938 | 39 (−68, 78) | ||
<65 y | 66 | 6 | 5558 | 265 | 2 (−138, 60) | 0.346 | ||
≥65 y | 10 | 1 | 1687 | 673 | 99 (1, 100) | |||
A (H3N2) | Any | 1840 | 221 | 7245 | 938 | 25 (13, 35) | ||
<65 y | 1124 | 46 | 5558 | 265 | 31 (1, 51) | 0.703 | ||
≥65 y | 716 | 175 | 1687 | 673 | 19 (−10, 40) | |||
B/Yamagata | Any | 108 | 9 | 7245 | 938 | 41 (−110, 84) | ||
<65 y | 73 | 3 | 5558 | 265 | 7 (−178, 69) | 0.203 | ||
≥65 y | 35 | 6 | 1687 | 673 | 73 (−38, 95) | |||
B/Victoria | Any | 618 | 25 | 7245 | 938 | 43 (−15, 71) | ||
<65 y | 596 | 24 | 5558 | 265 | 27 (−14, 54) | 0.191 | ||
≥65 y | 22 | 1 | 1687 | 673 | 89 (40, 98) | |||
Targeted groups only | Any | Any | 2314 | 256 | 4723 | 869 | 27 (16, 37) | |
<65 y | 1432 | 61 | 3036 | 196 | 37 (0, 47) | 0.657 | ||
≥65 y | 882 | 195 | 1687 | 673 | 25 (3, 43) | |||
A (H1N1) pdm09 | Any | 54 | 7 | 4723 | 869 | 18 (−142, 72) | ||
<65 y | 44 | 6 | 3036 | 196 | −62 (−303, 35) | 0.423 | ||
≥65 y | 10 | 1 | 1687 | 673 | 99 (1, 100) | |||
A (H3N2) | Any | 1572 | 214 | 4723 | 869 | 23 (9, 34) | ||
<65 y | 856 | 39 | 3036 | 196 | 27 (−7, 50) | 0.485 | ||
≥65 y | 716 | 175 | 1687 | 673 | 19 (−10, 40) | |||
B/Yamagata | Any | 63 | 7 | 4723 | 869 | 72 (8, 92) | ||
<65 y | 28 | 1 | 3036 | 196 | 65 (−35, 91) | 0.037 | ||
≥65 y | 35 | 6 | 1687 | 673 | 73 (−38, 95) | |||
B/Victoria | Any | 449 | 14 | 4723 | 869 | 66 (3, 80) | ||
<65 y | 427 | 13 | 3036 | 196 | 41 (10, 62) | 0.262 | ||
≥65 y | 22 | 1 | 1687 | 673 | 89 (40, 98) |
Discussion
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Although the same protocol was developed, the adaptation to different countries or sites produced some heterogeneity in the results, as previously reported in the network [3].
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In general vaccination coverage was low in most sites, even among high risk groups.
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Other factors as number of cases per site, and variability in the vaccination coverage, increased the heterogeneity in the reporting and analysis.
Conclusion
Acknowledgements
Funding
Availability of data and materials
Ethics approval and consent to participate
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St. Petersburg: Local Ethical Committee under the FGBU “Research Institute of Influenza” of the Ministry of Health of the Russian Federation
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Moscow: The local Ethic Committee of Hospital #1 for Infectious Diseases of Moscow Health Department
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Kazakhstan: The study was carried in Almaty, Kazakhstan as part of the implementation of the national Severe Acute Respiratory Infections (SARI) surveillance program in Kazakhstan for purposes of communicable disease control. Ethical approval was not required but informed consent was obtained before inclusion. Informed consent provided in accordance with the Constitution of the Republic of Kazakhstan (section II article 29)
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Czech Republic: Ethics Committee of the Hospital Na Bulovce
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Canada: The Nova Scotia Health Authority Research Ethics Board and the IWK Research Ethics Board (IWK: Isaak Walton Killam)
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Romania: Bioethics Committee of the National Institute for Infectious Diseases “Prof. Dr. Matei Bals” Bucharest, Romania
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Turkey: Hacettepe University Non-interventional Clinical Research Ethics Board
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Valencia: Comité Ético de Investigación Clínica Dirección General de Salud Pública-Centro Superior de Investigación en Salud Pública (CEIC-DGSP-CSISP)
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Tunisia: The ethics committee of Abderrahmane Mami hospital, Ariana, Tunisia
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Suzhou/Shanghai: Fudan University School of Public Health Institutional Review Board
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India: Institutional Ethics Committee of the Sher-i-Kashmir Institute of Medical Sciences, Srinagar
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Mexico: Research Ethics Committee of the National Institute of Medical Science and Nutrition Salvador Zubiran & Research Committee of the National Institute of Medical Science and Nutrition Salvador Zubiran
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South Africa: The Human Research Ethics Committee of the University of the Witwatersrand