Table 1.
Characteristics of the participants in the Omicron and control groups before propensity score matching.
| Characteristics | Omicron group |
Control group |
SMD | p-valuea |
|---|---|---|---|---|
| (n = 53) | (n = 502) | |||
| Age (years), median (IQR) | 56.0 (35.0, 69.5) | 48.0 (42.0, 55.0) | 0.011 | |
| Older adultb, No. (%) | 17 (32.1)c | 24 (4.8) | 0.767 | <0.001 |
| Female sex, No. (%) | 14 (26.4) | 300 (59.8) | 0.714 | <0.001 |
| BMId, median (IQR) | 24.4 (22.2, 26.8) | 23.1 (20.7, 25.9) | 0.045 | |
| Obesitye, No. (%) | 23 (43.4) | 150 (30.0) | 0.281 | 0.045 |
| Ethnicity, No. (%) | ||||
| Japanese | 44 (83.0) | 502 (100) | ||
| Asian | 4 (7.5) | 0 (0.0) | ||
| Caribbean | 3 (5.7) | 0 (0.0) | ||
| African | 2 (3.8) | 0 (0.0) | ||
| Smoking history, No. (%) | ||||
| Yes | 25 (47.2) | 206 (41.0) | 0.225 | |
| Individual comorbidities, No. (%) | ||||
| No medical conditions | 27 (50.9) | 234 (46.6) | 0.885 | |
| Hypertension | 10 (18.9) | 70 (13.9) | 0.450 | |
| Dyslipidemia | 10 (18.9) | 59 (11.8) | 0.200 | |
| Diabetes | 4 (7.5) | 19 (3.8) | 0.277 | |
| COPD | 1 (1.9) | 2 (0.4) | 0.275 | |
| Bronchial asthma | 3 (5.7) | 69 (13.7) | 0.700 | |
| Myocardial infarction | 1 (1.9) | 0 (0.0) | 0.102 | |
| Malignancy | 8 (15.1) | 11 (2.2) | <0.001 | |
| Immunodeficiency | 1 (1.9) | 2 (0.4) | 0.275 | |
| Chronic kidney disease | 2 (3.8) | 2 (0.4) | 0.053 | |
| Vaccinationf, No. (%) | 45 (84.9) | 11 (2.2) | 2.994 | <0.001 |
| Acute COVID-19 characteristics, No. (%) | ||||
| Pneumonia diagnosed | 12 (22.6) | 141 (28.1) | 0.214 | |
| Severityg | 0.173 | |||
| Mild | 42 (79.2) | 393 (78.3) | ||
| Moderate | 11 (20.8) | 58 (12.7) | ||
| Severe | 0 (0.0) | 4 (0.9) | ||
| Pharmacological treatments | ||||
| Antiviral | 13 (24.5) | 56 (11.2) | 0.020 | |
| Corticosteroids | 12 (22.6) | 58 (11.6) | 0.067 | |
| mAbh | 13 (24.5) | 4 (0.8) | <0.001 | |
Abbreviations: SMD, standardized mean difference; BMI, body mass index; IQR, interquartile range; COPD, chronic obstructive pulmonary disease; COVID-19, coronavirus disease 2019; IMV, invasive mechanical ventilation.
Mann–Whitney U test for continuous variables, Fisher's exact test or Kruskal−Wallis test for categorical variables.
Older adult is defined as aged 65 or more.
The denominator in each category depends on the number of missing values.
Calculated as weight in kilograms divided by height in meters squared.
Obesity is defined as BMI of 25 or more.
Patients tested positive for SARS-CoV-2 at least 7 days after their second vaccination when immunity had developed.
Highest severity during clinical course of COVID-19.
Monoclonal antibodies were either casirivimab/imdevimab or sotrovimab.