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Table 7 Characteristics of patients included in the primary analysis by vaccination status

From: Influenza epidemiology and influenza vaccine effectiveness during the 2014–2015 season: annual report from the Global Influenza Hospital Surveillance Network

Risk variables Category Unvaccinated Vaccinated P value
n % N %
Number of patients, n (%) Controls 4872 75.5 1556 77.7 0.042
  Cases 1581 24.5 446 22.3  
Age (y) Median (range) 14.6 (0.8-84.0) 78.7 (9.0-91.9) <0.001
Age group, n (%) 6–11 mo 496 7.7 3 0.1  
  1–4 y 2120 32.9 49 2.4  
  5–17 y 712 11.0 102 5.1  
  18–49 y 1347 20.9 75 3.7  
  50–64 y 591 9.2 138 6.9  
  65–74 y 388 6.0 416 20.8  
  75–84 y 512 7.9 704 35.2  
  ≥85 y 287 4.4 515 25.7  
Female, n (%) - 2825 43.8 843 42.1 0.188
Comorbidities, n (%) None 4505 70 366 18.3 <0.001
  1 1077 16.7 647 32.3  
  >1 871 13.5 989 49.4  
Pregnant, n (%) - 294 4.6 3 0.1 <0.001
Obesity, n (%) - 982 15.2 564 28.2 <0.001
Morbid obesity, n (%) - 86 1.3 54 2.7 <0.001
Previous hospitalisation within 12 months, n (%) - 1887 29.2 761 38 <0.001
GP visit within 3 months, n (%) None 1815 28.1 343 17.1 <0.001
  1 2027 31.4 389 19.4  
  >1 2606 40.4 1272 63.5  
Smoking, n (%) Current 1527 23.7 225 11.2 <0.001
  Past 1069 16.6 742 37.1  
  Never 3856 59.8 1035 51.7  
Functional impairment in ≥65 y, n (%) None or minimal 619 54.2 1021 62.4 <0.001
  Mild 324 28.4 330 20.2  
  Moderate 95 8.3 88 5.4  
  Severe 32 2.8 62 3.8  
  Total 72 6.3 123 7.5  
Sampling interval (days) Median (range) 3 (1-7) 4(1-7) <0.001
Sampling interval, n (%) ≤4 d 3703 57.4 990 49.5 <0.001
  5-7 d 2587 40.1 936 46.8  
  8-9 d 163 2.5 76 3.8  
Site, n (%) St. Petersburg 2138 33.1 59 2.9 <0.001
  Moscow 1306 20.2 39 1.9  
  Turkey 503 7.8 26 1.3  
  Beijing 996 15.4 127 6.3  
  Valencia 1510 23.4 1751 87.5  
Vaccinated, n (%)
  In 2012–2013 473 7.5 1471 73.3 <0.001
  In 2013–2014 513 8.1 1722 87.1 <0.001