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Table 2 Demographic and baseline characteristics

From: Intradermal influenza vaccination of healthy adults using a new microinjection system: a 3-year randomised controlled safety and immunogenicity trial

  Year 1
  3 μg ID
(N= 378)
6 μg ID
(N= 375)
15 μg IM
(N= 376)
Total
(N= 1129)
Mean age ± standard deviation 39 ± 11 39 ± 12 39 ± 12 39 ± 12
Male/female ratio 0.6 0.7 1.0 0.7
History of influenza vaccination*, n (%) 112 (29.6) 114 (30.4) 100 (26.6) 326 (28.9)
Reaction to previous influenza vaccination*, n (%) 10 (8.9) 9 (7.9) 7 (7.0) 26 (8.0)
  Year 2
  9 μg ID
( N = 544)
15 μg IM
( N = 547)
Total
( N = 1091)
mean age +/- standard deviation 40 ± 12 40 ± 12 40 ± 11
Male/female ratio 0.7 0.7 0.7
  Year 3
  9 μg ID
( N = 417)
15 μg IM
( N = 411)
Total
( N = 828)
mean age +/- standard deviation 41 ± 11 40 ± 11 40 ± 11
Male/female ratio 0.8 0.7 0.7
  1. Data are for the per protocol population for Year 1 and the safety population for Years 2 and 3. ID, intradermal; IM, intramuscular; N and n, number of subjects
  2. *Subjects who recalled having previously received an influenza vaccination and having experienced any reactions after a previous influenza vaccination.