Passive immunity occurs when a woman transfers antibodies to her child, and it can be triggered by a mother being vaccinated or infected during pregnancy. It occurs with COVID, as well as many other diseases.
COVID-specific antibodies have been discovered in umbilical cord blood from pregnancies of women who either caught the virus or were vaccinated against it during their pregnancy, indicating that the virus's immunological protection is passed down from mother to unborn child.
These antibodies should provide improved protection against COVID in the early stages of life for the newborn. New research from the US Centers for Disease Control and Prevention suggests that this is indeed the case.
The study was conducted between July 2021 and January 2022. It looked at 379 babies under the age of six months who were admitted to the hospital. They were two months old on average.
The infants were divided into two groups. The first group consisted of babies who were hospitalized with COVID symptoms and tested positive for the virus. The second group included babies who were admitted to the hospital with suspected COVID or for other reasons and later tested negative for the virus.
This type of study is known as a "case-control" study because cases (babies with COVID) are matched with "controls" (babies without COVID).
The researchers then analyzed the vaccination status of each group's moms to discover if the babies with COVID had unvaccinated mothers.
All of the infants tested had either unvaccinated moms or mothers who had received two doses of an mRNA COVID vaccine. Vaccinated moms had to have received their second dose during pregnancy and at least 14 days before giving birth to be eligible.
There was a difference, according to the researchers. Only 16% of COVID-affected kids had mothers who had been vaccinated, but the incidence of maternal vaccination was twice that of COVID-free newborns - 32%, a statistically significant difference - implying a preventive effect.
Some of the COVID-positive babies were brought to intensive care, and their mothers were unvaccinated in 88% of the cases. The only infant in the study who died was born to a mother who had not been vaccinated.
We know that administering COVID vaccines to pregnant women is safe for both mother and child. We now know that maternal vaccines appear to equip infants with immunity that protects them from serious disease. We also know that getting vaccinated during pregnancy reduces the incidence of COVID-related problems.
Vaccinating during pregnancy is therefore critical. The Royal College of Obstetricians and Gynaecologists recommends that pregnant women receive the entire course of COVID vaccines, including the booster.
