A Hadassah Medical Organization study reveals that newborns are better protected from COVID-19 if their mothers are vaccinated between weeks 27 and 31 of their pregnancies, rather than later on in the third trimester.

According to the study authors Dr. Amihai Rottenstreich, Dr. Shay Porat, and Prof. Dana Wolf, when pregnant women are vaccinated during this window of time, their unborn babies receive a higher level of antibodies than those inoculated later in the pregnancy.

The study cohort consisted of 171 women, where 83 received their first dose of the COVID-19 vaccine at 27-31 weeks and 88 were immunized with their first dose at 32-36 weeks. The authors’ analysis led them to conclude that early third-trimester immunization should afford adequate protection from COVID-19 infection during early infancy.

The authors add that their findings are ”in accordance with previous reports evaluating the effect of maternal pertussis and influenza immunization, showing augmented transplacental transfer and neonatal antibody levels along with improved clinical outcomes, following early third-trimester vaccination.”

At the same time, the researchers note that “there is a critical need for further scientific evidence to inform the ideal timing for vaccination during pregnancy that would provide mothers and neonates with the highest clinical protection against COVID-19.”

The study findings appear in Clinical Microbiology and Infection.