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. 2021 Oct 7;176(1):1–10. doi: 10.1001/jamapediatrics.2021.4251

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.