Pregnant women vaccinated against COVID-19 could pass along protection to their babies, according to a new study in Israel.

According to the research conducted in February, antibodies were detected in all 20 women administered both doses of the Pfizer/BioNTech vaccine during their third trimester of pregnancy and in their newborns, through placental transfer.

"Our findings highlight that vaccination of pregnant women may provide maternal and neonatal protection from SARS-CoV-2 infection," the study said.

The findings by researchers from Jerusalem's Hadassah- University Medical Center were posted this month on medRxiv - an online distribution service for unpublished research manuscripts that have not been peer-reviewed - and reported by Israeli media on Tuesday.

Pfizer Inc and BioNTech SE said last month they had started a 4,000-volunteer international study to evaluate the safety and effectiveness of their COVID-19 vaccine in healthy pregnant women.