Table 1.
Subject Demographics at Baseline
| 2017–2018 Season | 2018–2019 Season | |||||
|---|---|---|---|---|---|---|
| Characteristic | aIIV3 (n = 524 223) | IIV4 (n = 917 609) | HD-IIV3 (n = 3 377 860) | aIIV3 (n = 1 031 145) | IIV4 (n = 915 380) | HD-IIV3 (n = 3 809 601) |
| Mean age, y, ± SD | 75.0 ± 6.7 | 74.3 ± 7.1 | 75.2 ± 6.8 | 75.1 ± 6.8 | 74.2 ± 7.2 | 75.2 ± 6.9 |
| Female sex, n (%) | 310 833 (59) | 541 754 (59) | 1 984 013 (59) | 609 857 (59) | 540 494 (59) | 2 244 405 (59) |
| Race and ethnicity, n (%) | ||||||
| White | 289 145 (55) | 491 386 (54) | 1 903 939 (56) | 555 511 (54) | 444 375 (49) | 2 051 209 (54) |
| Black or African American | 18 212 (3) | 43 506 (5) | 130 576 (4) | 32 649 (3) | 46 765 (5) | 144 802 (4) |
| Other | 37 040 (7) | 90 759 (10) | 258 550 (8) | 83 411 (8) | 91 573 (10) | 308 299 (8) |
| Race not reported | 179 826 (34) | 291 958 (32) | 1 084 795 (32) | 359 574 (35) | 332 667 (36) | 1 305 291 (34) |
| Hispanic ethnicity | 18 886 (4) | 47 793 (5) | 94 301 (3) | 33 485 (3) | 56 266 (6) | 107 868 (3) |
| Geographic region, n (%) | ||||||
| Northeast | 77 130 (15) | 168 679 (18) | 659 746 (20) | 158 852 (15) | 178 324 (19) | 703 716 (18) |
| Midwest | 50043 (10) | 170 779 (19) | 720 252 (21) | 132 619 (13) | 157 087 (17) | 792 204 (21) |
| South | 318 905 (61) | 338 010 (37) | 1 264 537 (37) | 582 846 (57) | 335 573 (37) | 1 413 291 (37) |
| West | 54 361 (10) | 203 600 (22) | 602 689 (18) | 108 404 (11) | 199 288 (22) | 746 260 (20) |
| Not reported/other | 23 784 (5) | 36 541 (4) | 130 636 (4) | 48 424 (5) | 45 108 (5) | 154 130 (4) |
| CCI ± SD | 0.71 ± 1.33 | 0.86 ± 1.39 | 0.78 ± 1.34 | 0.71 ± 1.32 | 0.86 ± 1.39 | 0.79 ± 1.35 |
Abbreviations: aIIV3, adjuvanted trivalent inactivated influenza vaccine; CCI, Charlson Comorbidity Index; HD-IIV3, nonadjuvanted high-dose trivalent inactivated influenza vaccine; IIV4, nonadjuvanted quadrivalent inactivated influenza vaccine; SD, standard deviation.