Safety and efficacy of inactivated COVID-19 vaccines in women vaccinated during the first trimester of pregnancy.

OBJECTIVES

This study aimed to investigate the safety of the inactivated COVID-19 vaccines in early pregnant women in view of their adverse-effect profile and associated maternal-fetal complications, as well as to evaluate their immunogenicity.

METHODS

In this prospective observational cohort study, 232 women in their first trimester or those in the periconception period who inadvertently received two doses of inactivated COVID-19 vaccine between January 21, 2021, and January 14, 2022 were analyzed. Meanwhile, 735 unvaccinated early pregnancy women were also included in the study at a case-to-control ratio of 1:3.

RESULTS

The vaccination group did not have an increased miscarriage rate compared with that of the control group (P = 0.918). Furthermore, the birth defect rates in the vaccine group and control group were 0.83% and 1.0%, respectively. Vaccination did not increase the risk of small for gestational age, gestational diabetes mellitus, preterm, or hypertensive disorders of pregnancy (P >0.01). Within 12 weeks after the second dose, the inactivated vaccine effectively produced neutralizing antibody (NAb) against SARS-CoV-2. The NAb levels in the paired umbilical cord serum and maternal serum samples during delivery were negative in both groups. The T-cell subset remained within the normal range in both groups.

CONCLUSION

Therefore, our study proves that inactivated COVID-19 vaccines are safe for mothers and fetuses and also effective in producing NAb against SARS-CoV-2.