Table 1. Baseline Demographics of Included Pediatric Populations From 8 US Health Systems in the Vaccine Safety Datalink, 2019 and 2020a.
| Characteristic | 2019, No. (%) | 2020, No. (%) | Total, No. |
|---|---|---|---|
| Study population for analysis of vaccine administration rates | |||
| Unique patients, No. | 1 399 708 | 1 402 227 | 2 801 935 |
| Age groupb | |||
| <24 mo | 217 210 (15.5) | 217 575 (15.5) | 434 785 |
| 4-6 y | 361 494 (25.8) | 362 307 (25.8) | 723 801 |
| 11-13 y | 406 760 (29.1) | 411 553 (29.4) | 818 313 |
| 16-18 y | 414 244 (29.6) | 410 792 (29.3) | 825 036 |
| Sexb | |||
| Male | 714 009 (51.0) | 715 970 (51.1) | 1 429 979 |
| Female | 685 610 (49.0) | 686 108 (48.9) | 1 371 718 |
| Race and ethnicityb | |||
| Asianc | 167 260 (11.9) | 166 956 (11.9) | 334 216 |
| Blackc | 101 690 (7.3) | 99 929 (7.1) | 201 619 |
| Hispanic | 452 040 (32.3) | 448 186 (32.0) | 900 226 |
| Whitec | 461 145 (33.0) | 448 044 (32.0) | 909 189 |
| All other races and data not availabled | 217 573 (15.5) | 239 112 (17.0) | 456 685 |
| Study population for analysis of up-to-date vaccination coverage status | |||
| Unique patients, No. | 39 113 | 40 373 | 79 486 |
| Milestone agee | |||
| 7 mo | 5805 (14.8) | 6142 (15.2) | 11 947 |
| 18 mo | 8783 (22.5) | 8763 (21.7) | 17 546 |
| 6 y | 7722 (19.8) | 8127 (20.1) | 15 849 |
| 13 y | 8454 (21.6) | 8894 (22.0) | 17 348 |
| 18 y | 8349 (21.3) | 8447 (20.9) | 16 796 |
| Sexe | |||
| Male | 19 562 (50.0) | 20 745 (51.4) | 40 307 |
| Female | 19 549 (50.0) | 19 627 (48.6) | 39 176 |
| Race and ethnicitye | |||
| Asianc | 5073 (13.0) | 5318 (13.2) | 10 391 |
| Blackc | 2757 (7.0) | 2758 (6.8) | 5515 |
| Hispanic | 12 384 (31.7) | 12 852 (31.8) | 25 236 |
| Whitec | 13 414 (34.3) | 13 498 (33.4) | 26 912 |
| All other races and data not availabled | 5485 (14.0) | 5947 (14.8) | 11 432 |
a
Includes data from January 6 through October 5, 2019, and January 5, 2020, through October 3, 2020.
b
Estimated based on enrollment in epidemiologic week 2 of each year.
c
Racial categories specified as Non-Hispanic.
d
Includes those reporting being non-Hispanic Hawaiian or Pacific Islander, non-Hispanic Native American, another race, or multiple races, as well as those whose data were unknown.
e
Estimated based on those reaching the milestone age in February of each year.