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Table 2 Demographics and clinical characteristics of TIV-vaccinated vs unvaccinated patients ≥16 years (all adults group)

From: Influenza vaccine effectiveness against influenza-related hospitalization during a season with mixed outbreaks of four influenza viruses: a test-negative case-control study in adults in Canada

  Not vaccinated
N = 587
TIV
N = 776
p-value
Age, years
 Mean (SD) 61.35 (19.76) 73.68 (14.94) <0.001
 Median (range) 64 (18–98) 76 (18–104)  
Age subgroups, n (%)
 16–49 years 161 (27.4) 53 (6.8) <0.001
 50–64 143 (24.4) 122 (15.7)  
 65–75 years 112 (19.1) 195 (25.1)  
 > 75 years 171 (29.1) 406 (52.3)  
Female, n (%) 337 (57.4) 420 (54.1) 0.248
BMI, kg/m2
 Mean (SD) 26.72 (6.66) 26.68 (7.16) 0.915
 Median (range) 25.49 (11.38–60.35) 25.67 (6.64–63.77)  
Obese (BMI ≥30 kg/m2), n (%) 136 (23.2) 196 (25.3) 0.480
 ≥ 1 co-morbidity, n (%)
 Cardiac disease 195 (33.2) 568 (73.2) <0.001
 Vascular disease 427 (55.0) 241 (41.1) <0.001
 Pulmonary disease 297 (50.6) 401 (51.7) <0.001
Smoking, n (%)
 Current 127 (21.6) 105 (13.5) <0.001
 Past 162 (27.6) 315 (40.6) <0.001
Admitted from a LTCF 15 (2.6) 70 (9.0) <0.001
≤4 prescribed medications before admission 287 (48.9) 169 (21.8) <0.001
  1. N number of patients, TIV trivalent influenza vaccine, SD standard deviation, BMI body mass index, LTCF long-term care facility
  2. Missing data: BMI: 29 not vaccinated (4.9%), 26 TIV-vaccinated (3.4%); Obesity: 29 not vaccinated (4.9%), 26 TIV-vaccinated (3.4%); Current smoking: 1 not vaccinated (0.2%), 11 TIV-vaccinated (1.4%); Past smoking: 131 not vaccinated (22.3%), 130 TIV-vaccinated (16.7%); Admitted from a LTCF: 0 not vaccinated (0.0%), 1 TIV-vaccinated (0.1%); ≤4 prescribed medications before admission: 10 not vaccinated (1.7%), 7 TIV-vaccinated (0.9%)