Table 1. Demographic and Clinical Characteristics in the Safety Population at Baseline.*.
| Characteristic | Placebo (N=1240) |
mRNA-1273 (N=2486) |
Total (N=3726) |
|---|---|---|---|
| Age — yr | 14.2±1.6 | 14.3±1.6 | 14.3±1.6 |
| Age category — no. (%) | |||
| 16–17 yr | 311 (25) | 648 (26) | 959 (26) |
| 12–15 yr | 929 (75) | 1838 (74) | 2767 (74) |
| Sex — no. (%) | |||
| Male | 632 (51) | 1283 (52) | 1915 (51) |
| Female | 608 (49) | 1203 (48) | 1811 (49) |
| Body-mass index — no. (%)† | |||
| <30 | 1146 (92) | 2316 (93) | 3462 (93) |
| ≥30 | 94 (8) | 170 (7) | 264 (7) |
| Race or ethnic group — no. (%)‡ | |||
| White race | 1041 (84) | 2085 (84) | 3126 (84) |
| Black race | 42 (3) | 83 (3) | 125 (3) |
| Asian race | 79 (6) | 142 (6) | 221 (6) |
| Native Hawaiian or Other Pacific Islander ethnic group | 0 | 2 (<1) | 2 (<1) |
| American Indian or Alaska Native ethnic group | 7 (1) | 12 (<1) | 19 (1) |
| Multiple races or ethnic groups | 50 (4) | 118 (5) | 168 (5) |
| Other ethnic group | 9 (1) | 27 (1) | 36 (1) |
| Not reported | 11 (1) | 11 (<1) | 22 (1) |
| Unknown | 1 (<1) | 6 (<1) | 7 (<1) |
| Hispanic or Latinx ethnic group — no. (%)‡ | |||
| Yes | 152 (12) | 280 (11) | 432 (12) |
| No | 1076 (87) | 2188 (88) | 3264 (88) |
| Not reported or unknown | 12 (1) | 18 (1) | 30 (1) |
| Race and ethnic group — no. (%)‡ | |||
| White non-Hispanic | 912 (74) | 1857 (75) | 2769 (74) |
| Communities of color | 325 (26) | 625 (25) | 950 (26) |
| Missing | 3 (<1) | 4 (<1) | 7 (<1) |
| RT-PCR test — no. (%) | |||
| Positive | 9 (1) | 13 (1) | 22 (1) |
| Negative | 1139 (92) | 2308 (93) | 3447 (93) |
| Missing data | 92 (7) | 165 (7) | 257 (7) |
| Anti–SARS-CoV-2 nucleocapsid assay result — no. (%) | |||
| Positive | 63 (5) | 139 (6) | 202 (5) |
| Negative | 1153 (93) | 2299 (92) | 3452 (93) |
| Missing | 24 (2) | 48 (2) | 72 (2) |
| SARS-CoV-2 status — no. (%)§ | |||
| Positive | 69 (6) | 147 (6) | 216 (6) |
| Negative | 1075 (87) | 2167 (87) | 3242 (87) |
| Missing data | 96 (8) | 172 (7) | 268 (7) |
| Median trial duration (range) — days | |||
| From randomization to database lock | 82 (9–151) | 84 (30–151) | 83 (9–151) |
| From second injection to database lock | 51 (0–121) | 53 (0–121) | 53 (0–121) |
Plus–minus values are means ±SD. Percentages may not total 100 because of rounding. RT-PCR denotes reverse-transcriptase polymerase chain reaction, and SARS-CoV-2 severe acute respiratory syndrome coronavirus 2.
The body-mass index is the weight in kilograms divided by the square of the height in meters.
Race or ethnic group was reported by the participant. Participants could be included in more than one category.
Baseline SARS-CoV-2 status was positive if there was immunologic or virologic evidence of previous illness with Covid-19, as defined by a positive RT-PCR test or a positive immunoassay result (i.e., detection of binding antibodies against the SARS-CoV-2 nucleocapsid [Elecsys, Roche] above the limit of detection or the lower limit of quantification at day 1). Baseline SARS-CoV-2 status was negative if there was a negative RT-PCR test and a negative immunoassay result (i.e., no detection of binding antibodies against the SARS-CoV-2 nucleocapsid [Elecsys, Roche] below the limit of detection and the lower limit of quantification at day 1).