After studying the effects of vaccination on unborn babies, the CDC found that infants that were younger than 6 months old were 61% less likely to be hospitalized with Covid if their mother received a vaccine from Pfizer or Moderna while pregnant. Research suggests that this is possible because antibodies from the vaccine can transfer across the placenta to the fetus. For mothers that got vaccinated later in the pregnancy, 21 weeks to 14 days before delivery, the baby had an even higher level of protection. It went from 61% to 80%.