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Table 6 IVE for all cases and for targeted groups only by age and strain

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

    Influenza-positive Influenza-negative Crude IVE Adjusted IVE
Population Strain Age Total Vaccinated Total Vaccinated Percent (95 % CI) P interaction Percent (95 % CI) P interaction
Overall Any Any 2027 446 6428 1556 -1 (-17, 12)   22 (8, 33)  
  <65 y 1334 78 4299 289 -4 (-36, 20) 0.090 -5 (-38, 20) 0.054
  ≥65 y 693 368 2129 1267 21 (5, 34) 24 (9, 37)
A(H3N2) Any 1165 356 6428 1556 -6 (-24, 10)   20 (4, 33)  
  <65 y 630 50 4299 289 -15 (-59, 17) 0.036 -16 (-64, 17) 0.031
  ≥65 y 535 306 2129 1267 24 (7, 37) 25 (8, 39)
A(H1N1) Any 104 7 6428 1556 25 (-85, 69)   27 (-82, 71)  
  <65 y 91 3 4299 289 16 (-173, 74) 0.996 21 (-161, 76) 0.993
  ≥65 y 13 4 2129 1267 47 (-128, 88) 59 (-83, 91)
B/Yamagata Any 625 57 6428 1556 16 (-17, 39)   31 (2, 52)  
  <65 y 509 20 4299 289 7 (-51, 42) 0.266 29 (-17, 58) 0.273
  ≥65 y 116 37 2129 1267 38 (-2, 62 33 (-12, 61)
Targeted groups only Any Any 1670 425 5077 1462 13 (-2, 26)   23 (8, 35)  
  <65 y 977 57 2948 195 -21 (-70. 14) 0.037 -12 (-58, 20) 0.019
  ≥65 y 693 368 2129 1267 26 (16, 42) 28 (14, 41)
H3N2 Any 994 344 5077 1462 13 (-4, 28)   22 (5, 36)  
  <65 y 459 38 2948 195 -12 (-65, 24) 0.051 -20 (-80. 21) 0.030
  ≥65 y 535 306 2129 1267 27 (11, 41) 28 (11, 42)
H1N1 Any 84 6 5077 1462 44 (-58, 80)   46 (-52, 81)  
  <65 y 71 2 2948 195 33 (-198, 85) 0.793 39 (-167, 86) 0.770
  ≥65 y 13 4 2129 1267 47 (-128, 88) 50 (-111, 89)
B/Yamagata Any 486 49 5077 1462 21 (-18, 46)   30 (-5, 53)  
  <65 y 370 12 2948 195 -8 (-105, 44) 0.139 8 (-79, 53) 0.250
  ≥65 y 116 37 2129 1267 38 (-2, 62) 33 (-12, 60)
  1. Abbreviation: IVE influenza vaccine effectiveness