Table 1 Characteristics of eligible United States influenza vaccine effectiveness enrollees in each study year
Variable | Category | 2013/14 A(H1N1)pdm | 2015/16 any influenza | 2017/18 A(H3N2) |
|---|---|---|---|---|
Total | 1542 | 7372 | 7428 | |
Site | MI | 245 (16%) | 1076 (15%) | 1257 (17%) |
PA | 262 (17%) | 1820 (25%) | 1188 (16%) | |
TX | 297 (19%) | 1395 (19%) | 1738 (23%) | |
WA | 256 (17%) | 1825 (25%) | 1418 (19%) | |
WI | 482 (31%) | 1256 (17%) | 1827 (25%) | |
Age group | < 5 years | 512 (33%) | 1148 (16%) | 1193 (16%) |
5–8 years | 433 (28%) | 631 (9%) | 560 (8%) | |
9–17 years | 597 (39%) | 898 (12%) | 920 (12%) | |
18–49 years | excla | 2567 (35%) | 2510 (34%) | |
50–64 years | excl | 1245 (17%) | 1252 (17%) | |
≥65 years | excl | 883 (12%) | 993 (13%) | |
High Risk | 348 (23%) | 3004 (41%) | 3536 (48%) | |
Vaccinated | Any vaccine | 689 (45%) | 3479 (47%) | 3759 (51%) |
LAIVb | 172 (25%) | 164 (5%) | 0 (0%) | |
Influenza | A(H1N1)pdm | 212 (14%) | 778 (11%) | excl |
A(H3N2) | excl | 79 (1%) | 1774 (24%) | |
B | excl | 473 (6%) | excl |