Israeli research: COVID vaccine antibodies pass from pregnant mother to baby

A new study by researchers at Hadassah-University Medical Center showed that pregnant women vaccinated against the coronavirus can transmit their immunity to their babies.

The study, which has so far only been published in MedRxiv and therefore has not been peer-reviewed, assessed the level of immunoglobulin G (IgG) antibodies in 20 pregnant women who received two injections of the Pfizer vaccine against the coronavirus during the third trimester. , and their babies. In all cases, these antibodies were detected at adequate levels in the mothers’ blood and in the umbilical cord blood.

“Neonatal protection against infection depends mainly on antibodies derived from the mother that are transferred by the placenta,” Dana Wolf, director of Hadassah’s Clinical Virology Unit, told The Jerusalem Post. “We demonstrated an efficient placental transfer of IgG antibodies – the type of antibodies that are triggered by infection or after vaccination.”

The researchers specifically measured the level of antibodies against the SARS-CoV-2 spike protein and its receptor-binding domain, which would show whether the antibodies protect against COVID-19. Wolf said the level and type of antibodies suggest “being able to block the virus sufficiently”.

The study was carried out in February, shortly after the first pregnant women began to be vaccinated in Israel. Wolf said the study is ongoing and the team is now evaluating the level of antibodies in women who were vaccinated in early pregnancy as well.

Wolf, who worked on the study with a handful of other experts – including obstetricians Dr. Amihai Rottenstreich and Shay Porat – said the group will now begin to analyze how long antibodies will last in babies.

The transfer of antibodies across the placenta is not uncommon. For example, pregnant women are commonly vaccinated against pertussis to protect their newborns from developing the disease.

Since the beginning of the third wave, dozens of pregnant women ended up in intensive care units after contracting COVID-19. In most cases, they were forced to deliver their babies earlier through emergency caesarean sections. In the worst cases, some women died.

Wolf said that “the vaccine protects women from serious illnesses and we now believe that it can also help protect their babies during early life.”

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