Patients’ baseline characteristics
| Total number of patients | 552 |
|---|---|
| Sex ratio (M/F) | 1.3 |
| Age (years) | |
| Median | 2.1 |
| IQR | 1–3.5 |
| Range | 0–15.7 |
| Age groups distribution | N (%) |
| 0–4 years | 512 (93) |
| <3 months | 21 (4) |
| <1 year | 137 (25) |
| 5–14 years | 40 (7) |
| Ethnicity | N (%) |
| Caucasian | 307 (56) |
| North Africa | 50 (9) |
| Sub-Saharan Africa | 17 (3) |
| Asia | 17 (3) |
| South America | 5 (1) |
| Oceania | 1 (0.2) |
| Unknown | 155 (28) |
| Comorbidity | N (%) |
| Lung disease | 22 (4) |
| Asthma | 17 (3) |
| Neurological disorder | 11 (2) |
| Renal disease/uropathy | 10 (2) |
| Cancer | 6 (1) |
| Cardiac disease | 6 (1) |
| Gastrointestinal disease | 5 (1) |
| Immunosuppressive therapy | 3 (0.5) |
| Congenital immunodeficiency | 3 (0.5) |
| Congenital malformation | 3 (0.5) |
| Haematological disorder | 2 |
| Metabolic disorder | 1 |
| Varicella vaccine status | N (%) |
| Unvaccinated | 322 (58) |
| 1 dose | 4 (1) |
| Unknown | 226 (41) |