Fig. 1.

Overview of the study design. Female rats were administered four intramuscular injections (2 prior to cohabitation with the males and 2 during gestation) of saline (control) or BNT162b2 (44/group). On each dosing day, animals were administered the full human dose (30 μg mRNA/dose) by intramuscular injection into the quadriceps muscle. Approximately half the rats (n = 22/group) underwent cesarean section on gestation day (GD) 21. The remaining rats (n = 22/group) were allowed to deliver naturally, and the maternal animals and offspring were followed through to the end of weaning. Blood was collected for measurement of antibody response in maternal animals prior to the first dose, at mating, end of gestation, and end of lactation. Blood was collected from fetuses at the end of gestation and from the littered offspring at the end of lactation.