TABLE 2

VE of Current Season Vaccine Against Influenza A Viruses Stratified by Vaccine Receipt in the Season Before Enrollment

VaccinationTotalNo. Influenza-Positive (%)aNo. Influenza-Negative (%)aAdjustedb VE, %95% CI
Influenza A/H1N1pdm09c
 Prior season unvaccinated
  Current season IIV56728 (5)539 (95)7764 to 85
  Current season LAIV21332 (15)181 (85)25−9 to 49
  Current season unvaccinated3311542 (16)2769 (84)Ref
 Prior season IIV
  Current season IIV141298 (7)1314 (93)4615 to 66
  Current season LAIV22029 (13)191 (87)−19−126 to 38
  Current season unvaccinated85997 (11)762 (89)Ref
 Prior season LAIV
  Current season IIV21716 (7)201 (93)7355 to 84
  Current season LAIV32957 (17)272 (83)24−16 to 50
  Current season unvaccinated29258 (20)234 (80)Ref
Influenza A/H3N2d
 Prior season unvaccinated
  Current season IIV45072 (16)378 (84)3516 to 50
  Current season LAIV21461 (29)153 (72)−38−106 to 7
  Current season unvaccinated2963605 (20)2358 (80)Ref
 Prior season IIV
  Current season IIV1226196 (16)1030 (84)3610 to 54
  Current season LAIV30655 (18)251 (82)28−12 to 54
  Current season unvaccinated980198 (20)782 (80)Ref
 Prior season LAIV
  Current season IIV14429 (20)115 (80)12−35 to 43
  Current season LAIV40290 (22)312 (78)13−30 to 42
  Current season unvaccinated28570 (25)215 (75)Ref
  • Analyses exclude N = 62 patients for whom parent- or guardian-reported, current season vaccination could not be confirmed by EIRs (USAFSAM), N = 10 who received IIV and LAIV in the season before enrollment, N = 560 with unavailable records for the season before enrollment, and N = 53 with an unknown vaccine type in the season before enrollment. Ref, reference group; —, not applicable.

  • a Percent of row total.

  • b Adjusted for age (years), season, calendar time, and site (as a random effect).

  • c Restricted to the 2013–2014 and 2015–2016 influenza seasons.

  • d Restricted to the 2014–2015 influenza season.