Table 1A. Baseline characteristics of the cohorts in influenza analysis, Stockholm County, influenza seasons 2011/12 and 2012/13.
| Characteristic | Influenza season 2011/12 | Influenza season 2012/13 | ||||
|---|---|---|---|---|---|---|
| Total | Vaccinateda | Unvaccinated | Total | Vaccinateda | Unvaccinated | |
| n | n (%) | n (%) | n (%) | n (%) | n (%) | |
| Cohort total | 2,089,047 | 205,415 (9.8) | 1,883,612 (90.2) | 2,121,469 | 185,646 (8.8) | 1 935,823 (91.2) |
| Sex | ||||||
| Male | 1,034,494 | 87,659 (8.5) | 946,835 (91.5) | 1,051,818 (49.6) | 79,920 (7.6) | 971,898 (92.4) |
| Female | 1,054,553 | 117,756 (11.2) | 936,797 (88.8) | 1,069,651 (50.4) | 105,726 (9.9) | 963,925 (90.1) |
| Age group in years | ||||||
| < 10 | 270 | 388 (0.1) | 270,435 (99.9) | 276,358 (13.0) | 273 (0.1) | 276,085 (99.9) |
| 10–19 | 232 | 540 (0.2) | 231,971 (99.8) | 231,869 (10.9) | 388 (0.2) | 231,481 (99.8) |
| 20–29 | 283,977 | 1,373 (0.5) | 282,604 (99.5) | 291,993 (13.8) | 1,014 (0.4) | 290,979 (99.6) |
| 30–39 | 320,932 | 3,219 (1.0) | 317,713 (99.0) | 322,867 (15.2) | 2,437(0.8) | 320,430 (99.2) |
| 40–49 | 307,966 | 4,457 (1.4) | 303,509 (98.6) | 313,605 (14.8) | 3,499 (1.1) | 310,106 (98.9) |
| 50–59 | 241,944 | 8,340 (3.4) | 233,604 (96.6) | 246,848 (11.6) | 6,916 (2.8) | 239,932 (97.2) |
| 60–69 | 223,956 | 60,580 (27.0) | 163,376 (73.0) | 224,713 (10.6) | 52,719 (23.5) | 171,994 (76.5) |
| 70–79 | 121,415 | 73,510 (60.5) | 47,905 (39.5) | 127,570 (6.0) | 70,014 (54.9) | 57,556 (45.1) |
| ≥ 80 | 85,523 | 53,008 (62.0) | 32,515 (38.0) | 85,646 (4.0) | 48,386 (56.5) | 37,260 (43.5) |
| Mosaic income/education categories | ||||||
| Highest income and education | 945,893 | 94,506 (10.0) | 851,387 (90.0) | 971,845 | 85,992 (8.8) | 885,853 (91.2) |
| Middle income and education | 360,980 | 36,871 (10.2) | 324,109 (89.8) | 372,925 | 33,095 (8.9) | 339,830 (91.1) |
| Lowest income and education | 744,905 | 73,067 (9.8) | 671,838 (90.2) | 761,746 | 66,032 (8.7) | 695,714 (91.3) |
| Missing | 37,269 | 1,450 (3.9) | 35,819 (96.1) | 14,653 | 536 (3.7) | 14,117 (96.3) |
| Comorbidity | ||||||
| Yes | 586,470 | 148,196 (25.3) | 438,274 (74.7) | 613,183 (28.9) | 138,020 (22.5) | 475,163 (77.5) |
| No | 1,502,577 | 57,219 (3.8) | 1,445,358 (96.2) | 1,508,286 (71.1) | 47,626 (3.2) | 1,460,660 (96.8) |
| Previous seasonal vaccinationb | ||||||
| Yes | 203,736 | 162,379 (79.7) | 41,357 (20.3) | 198,361 (9.4) | 151,359 (76.3) | 47,002 (23.7) |
| No | 1,885,311 | 43,036 (2.3) | 1,842,275 (97.7) | 1,923,108 (90.7) | 34,287 (1.8) | 1,888,821 (98.2) |
| Pneumococcal vaccinationc | ||||||
| Yes | 33,374 | 28,232 (84.6) | 5,142 (15.4) | 39,502 (1.9) | 30,891 (78.2) | 8,611 (21.8) |
| No | 2,055,673 | 177,183 (8.6) | 1,878,490 (91.4) | 2,081,967 (98.1) | 154,755 (7.4) | 1,927,212 (92.6) |
| Pandemrix vaccinationd | ||||||
| Yes | 1,064,132 | 163,246 (15.3) | 861,669 (84.7) | 1,007,546 (47.5) | 148,338 (14.7) | 859,208 (85.3) |
| No | 1,024,915 | 42,169 (4.1) | 1,021,963 (95.9) | 1 113 923 (52.5) | 37,308 (3.4) | 1,076,615 (96.6) |
Influenza season defined as 1 October to 31 May in the following year.
a During the 2011/12 influenza season, 99.5% of seasonal influenza vaccinations were carried out using Vaxigrip. During 2012/13, 99.4% of seasonal influenza vaccinations were carried out using Fluarix.
b Vaccinated against seasonal influenza during the previous season.
c Vaccinated against Streptococcus pneumoniae during time period from 2009 to the season under investigation.
d Vaccinated against influenza A(H1N1)pdm09 during the 2009 pandemic.