Maternal Vaccination and Protective Immunity Against SARS‐CoV‐2 Infection in Pups

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had a devastating impact worldwide. Currently, several vaccines are approved for emergency use in humans, and these vaccines have played a large role in controlling COVID-19. Pregnant women and newborns constitute a special population for vaccine policy. Here, we established a maternal vaccination model by injecting pregnant mice with a SARS-CoV-2 receptor-binding domain (RBD) homodimer. Maternal immunization with the RBD dimer did not cause obvious adverse effects on pregnancy or fetal development. Moreover, two-shot immunization fully protected dams and fetuses from SARS-CoV-2 infection during pregnancy. Neutralizing antibodies can be transferred from immunized dams to pups, providing protection for both lactating and weaned pups against SARS-CoV-2 infection. Our results indicate that, in addition to being used to vaccinate nonpregnant individuals, the RBD dimer can also be considered for maternal vaccination.