Table 1.
Characteristics of participants at first visit.
| BNT162b2 Vaccination | SARS-CoV-2 Infection | ||
|---|---|---|---|
| No Milk Conversion (n = 26) | Milk Conversion (n = 2) 1 | (n = 18) | |
| Maternal features | |||
| Age, median (IQR), y | 33.5 (30.8–35) | 35.5 | 31 (28.5–36.5) |
| BMI, median (IQR), kg/m2 | 24.0 (21.0–26.6) | 25.8 | 25.8 (21.6–25.2) |
| Chronic disease, No. (%) | 3 (11.5) 2 | 0 (0) | 0 (0) |
| Parity primiparous, No. (%) | 12 (46.2) | 1 (50) | 9 (50) |
| Age postpartum, median (IQR), months | 7.0 (4.8–9.0) | 9 | 6.0 (4.5–8.5) |
| Delivery mode (vaginal), No. (%) | 19 (73.1) | 1 (50) | 12 (66.7) |
| Lactational stage, No. (%) | |||
| <6 months | 8 (30.8) | 1 (50) | 5 (27.8) |
| 6–12 months | 16 (61.5) | - | 11 (61.1) |
| >12 months | 2 (7.7) | 1 (50) | 2 (11.1) |
| Vaccination history, No. (%) | |||
| Child-immunization 3 | 26 (100) | 2 (100) | 16 (88.9) |
| Whooping cough vaccine during pregnancy | 25 (96.2) | 2 (100) | 15 (83.3) |
| Other | 14 (53.8) 4 | 1 (50) | 12 (66.7) 4 |
| Race/ethnicity, No. (%) | |||
| Europe | 25 (96.2) | 2 (100) | 14 (77.8) |
| Oceania | 1 (3.8) | - | 2 (11.1) |
| Africa | - | - | 1 (5.6) |
| South America | - | - | 1 (5.6) |
| Infant features | |||
| Birthweight, median (range), grams | 3388 (3126–3710) | 3495 | 3475 (3278–3848) |
| Gestational age, mean (SD), weeks | 39.1 (1.7) | 41 | 39.9 (1.5) |
| Sex of infant (female), No. (%) | 16 (61.5) | 1 (50) | 7 (38.9) |
| Exclusive breastfeeding, No. (%) | 12 (46.2) | 1 (50) | 7 (38.9) |
Abbreviations: IQR, interquartile range; BMI, body mass index; SD, standard deviation; 1 All values for two previously infected vaccinated women are presented in this table as mean; 2 Diabetes Mellitus type 1, epilepsy, hypothyroidism; 3 According to the Dutch National Immunization Program; 4 other vaccinations specified: hepatitis B and A, yellow fever, rabies, typhoid fever, influenza A, and cholera.