Table 1. Demographic and Clinical Characteristics of Vaccinated Children and Unvaccinated Controls at Baseline.*.
| Variable | Total Population Eligible for the Vaccinated Group (N=136,127) |
Vaccinated Group (N=94,728) |
Unvaccinated Group (N=94,728) |
|---|---|---|---|
| Median age (IQR) — yr | 8 (7–10) | 8 (7–10) | 8 (7–10) |
| Age distribution — no. (%) | |||
| 5 yr | 15,052 (11) | 10,576 (11) | 10,576 (11) |
| 6 yr | 18,412 (14) | 12,910 (14) | 12,910 (14) |
| 7 yr | 19,390 (14) | 13,577 (14) | 13,577 (14) |
| 8 yr | 19,770 (15) | 13,786 (15) | 13,786 (15) |
| 9 yr | 20,332 (15) | 14,088 (15) | 14,088 (15) |
| 10 yr | 20,924 (15) | 14,455 (15) | 14,455 (15) |
| 11 yr | 22,247 (16) | 15,336 (16) | 15,336 (16) |
| Female sex — no. (%) | 66,164 (49) | 46,083 (49) | 46,083 (49) |
| Population sector — no. (%) | |||
| General Jewish | 113,970 (84) | 79,560 (84) | 79,560 (84) |
| Arab | 16,098 (12) | 11,180 (12) | 11,180 (12) |
| Ultra-Orthodox Jewish | 6,059 (4.5) | 3,988 (4.2) | 3,988 (4.2) |
| Influenza vaccinations in the previous 5 yr — no. (%) | |||
| 0–2 | 77,556 (57) | 56,056 (59) | 56,056 (59) |
| ≥3 | 58,571 (43) | 38,672 (41) | 38,672 (41) |
| Overweight or obese status — no. (%)† | 26,350 (19) | 15,802 (17) | 15,802 (17) |
| No. of chronic diagnostic codes — no. (%) | |||
| 0 | 87,466 (64) | 63,641 (67) | 63,641 (67) |
| 1 | 27,756 (20) | 17,845 (19) | 17,845 (19) |
| ≥2 | 20,905 (15) | 13,242 (14) | 13,242 (14) |
| CDC risk factors for severe Covid-19 — no. (%) | |||
| Cancer | 80 (<0.1) | 48 (<0.1) | 62 (<0.1) |
| Chronic kidney disease | 2,566 (1.9) | 1,671 (1.8) | 1,714 (1.8) |
| Heart disease | 136 (<0.1) | 76 (<0.1) | 101 (0.1%) |
| Cerebrovascular disease | 80 (<0.1) | 53 (<0.1) | 91 (<0.1) |
| Neurologic disease | 1,281 (0.9) | 797 (0.8) | 954 (1.0) |
| Liver disease | 82 (<0.1) | 53 (<0.1) | 57 (<0.1) |
| Asthma | 5,429 (4.0) | 3,444 (3.6) | 3,646 (3.8) |
| Diabetes mellitus | |||
| Type 1 | 121 (<0.1) | 77 (<0.1) | 86 (<0.1) |
| Type 2 | 25 (<0.1) | 19 (<0.1) | 19 (<0.1) |
| Immunosuppression | 1,533 (1.1) | 986 (1.0) | 1,042 (1.1) |
| Hypertension | 48 (<0.1) | 30 (<0.1) | 35 (<0.1) |
| Solid-organ transplantation | 13 (<0.1) | 10 (<0.1) | 10 (<0.1) |
*
The 15,280 children who were first recruited as unvaccinated controls and then subsequently rerecruited as vaccinated children are counted in both groups. CDC denotes the Centers for Disease Control and Prevention, Covid-19 coronavirus disease 2019, and IQR interquartile range.
†
Overweight or obese status was defined as a body-mass index at the 85th percentile or higher (according to CDC growth charts).