Evaluation of SARS-CoV-2 vaccination in pregnant and breastfeeding women

OBJECTIVES: We aimed to assess the safety experience of women vaccinated with vaccines against SARS-CoV-2 during breastfeeding or pregnancy. METHODS: Via an online questionnaire, we have inquired about the safety experience of 2192 pregnant or breastfeeding women vaccinated against SARS-CoV-2, including the incidence of adverse events (AEs), pregnancy outcomes, and confirmed infection with SARS-CoV-2. RESULTS: The incidence of other AEs was higher in women vaccinated during breastfeeding. Significant differences were observed for fatigue (relative risk [RR] 1.230, 95% confidence interval [CI] 1.051-1.444, P = 0.0098), headache (RR 1.822, 95% CI 1.379-2.418, P <0.0001), myalgia (RR 1.633, 95% CI 1.269-2.110, P <0.0001), chills (RR 2.027, 95% CI, P <0.0001), subfebrile temperature ≤38°C (RR 1.697, 95% CI 1.240-2.335, P = 0.0007), arthralgia (RR 1.924, 95% CI 1.340-2.776, P = 0.0002), fever >38°C (RR 6.410, 95% CI 2.890-14.30, P <0.0001), and shivers (RR 2.204, 95% CI 1.264-3.863, P = 0.0049). No pattern of serious AEs emerged. Menstrual cycle bleeding disorders occurred in 0.7% of breastfeeding women after the first dose and 0.5% after the second dose. One spontaneous abortion occurred; 93.1% of pregnancies were carried to term, 5.6% late preterm, 0.9% moderate preterm, and 0.3% very preterm. Two children had congenital defects. Vaccine efficacy was 96.3%. CONCLUSION: The safety profile of SARS-CoV-2 vaccines in pregnant and breastfeeding women was similar to the general population. Breastfeeding women experienced higher AE rates than pregnant women, presumably due to immune alterations in pregnancy.