It is known that antibodies to infection are transmitted from mother to child during the third trimester of pregnancy, providing the child with some protection against this specific disease at birth, but little is known about the extent to which Covid-19 antibodies are transmitted from mother to child, whether in the vaccinated groups. or unfertilized.

The new study, presented at the European Conference on Clinical Microbiology and Infectious Diseases (ECCMID) in Lisbon, Portugal, focuses on pregnant women who contracted COVID-19 before vaccines were widely deployed.

Dr. Liliana Gabrielli and colleagues at the IRCCS Saint Ursula Medical Clinic at the University of Bologna in Italy studied more than 4,000 women who gave birth in Bologna between July 1, 2020 and March 31, 2021.

The women underwent PCR tests to check for covid-19 infection, and gave blood samples that were tested for antibodies, which provide evidence of previous infection.

How protect us from the "Corona" virus?

Vaccine expert brings good news to the world: Omicron is the beginning of the end of the epidemic

All newborns underwent PCR tests to check for COVID-19 and newborns whose mothers tested positive for the antibodies were also tested for antibodies.

136 of the women (3.4%) had Covid antibodies in their blood. 26% of these women had both IgG (older infection) and IgM (recent infection) antibodies. 74% of the women had IgG antibodies but negative IgM antibodies.

Blood samples were available from 73 children born to mothers with antibodies to COVID-19, none of the 73 children had IgM antibodies This was expected because IgM does not cross the placenta, 11 of the children were both IgG and IgM negative and the other 62 were IgG positive. All of the 73 children had negative sequencing reactions when tested shortly after birth, indicating that they did not have COVID-19 and that the antibodies had been passed on to them by their mother, rather than made by themselves. While antibody transmission was high, levels in newborns were slightly lower than in their mothers

Dr. Gabrielli says: “This study of pregnant women and their newborns, conducted in the pre-vaccination period, found that 3.4% of the women were infected with COVID-19 during pregnancy. "Most of these women pass the antibodies on to their babies, however, the protection these antibodies provide will gradually decrease over time and disappear within 100 days of birth in most cases," Gabrielli added.