THURSDAY, Nov. 4, 2021 (HealthDay News) — Mothers who had COVID-19 when they gave birth may help boost their babies’ budding immunity to the virus by breastfeeding, a small study has found.
It is well known that breast milk contains certain maternal antibodies that can help protect infants against infection as their own immune system develops.
Studies indicate that this is also true for SARS-CoV-2: the breast milk of mothers who have had COVID-19 or who have been vaccinated against it contains antibodies against the virus.
Antibodies passed from mother to baby – both in the womb and through breastfeeding – provide what is called “passive” immune protection, where the mother’s antibodies stand guard while the immune system of the baby is growing.
Now the new study suggests that breastfeeding after COVID-19 may also help stimulate a more “active” immune response in babies: It found that at 2 months of age, the saliva of breastfed infants contained some antibodies to SARS-CoV-2 “spike” protein.
“We have shown for the first time that the mother can also trigger the active immune response of the newborn through the transfer of antigen-antibody immune complexes,” said lead researcher Dr Rita Carsetti, of Children’s Hospital Bambino Gesù in Rome, Italy. .
These “complexes,” she explained, are maternal antibodies to which the spike protein is bound.
The results do not show whether these antibodies in saliva provide infants with additional protection against disease if they encounter SARS-CoV-2.
It’s possible they could help defend against the virus getting into a baby’s eyes or nose, Dr Tina Tan said. She is a professor of pediatrics at Northwestern University in Chicago and a spokesperson for the Infectious Diseases Society of America.
But, Tan said, the best way to transfer protective antibodies to babies is to get vaccinated during pregnancy: those antibodies cross the placenta and enter the fetal blood.
In this study, most infants did not have antibodies to SARS-CoV-2 in their blood.
At the start of the pandemic, no one knew if it was possible for mothers with COVID-19 to transmit the virus to their babies through breast milk. Later research showed that was not the case, and the guidelines encourage mothers with COVID-19 to continue breastfeeding (or start if they have just given birth) – but with precautions like wearing a baby shower. a mask.
The current study – published online November 3 in Open JAMA Network – included 22 newborns born to mothers who tested positive for SARS-CoV-2 at delivery. Only one child tested positive for the infection just after birth; another later tested positive a few days later.
Carsetti’s team found that at 2 months of age, breastfed infants had antibodies to the spike protein in their saliva. This was not the case with babies who were exclusively formula-fed.
When the researchers tested samples of mothers’ breast milk, they found that all harbored these key complexes – antibodies with a spike protein bound to them. Levels were particularly high two days after delivery; they had diminished after two months.
The study is significant because it’s the first demonstration that breastfeeding can “actively stimulate” an infant’s immune system to make salivary antibodies against SARS-CoV-2, Dr. Lori Feldman-Winter said.
Feldman-Winter, a professor of pediatrics at Rowan University’s Cooper Medical School in Camden, NJ, chairs the breastfeeding section of the American Academy of Pediatrics.
“Human milk is known to participate in the programming of the infant’s immune system during the first days of life,” she said. “Therefore, breast milk after COVID infection activated their infants’ immune systems to produce COVID-specific salivary antibodies, whereas formula-fed infants did not produce this response.”
Carsetti said research is ongoing, both to confirm current findings and to see if infants born to vaccinated mothers also show signs that their immune systems have been actively stimulated against the virus.
Like Tan, she pointed out that when pregnant women get vaccinated, their antibodies cross the placenta.
The American College of Obstetricians and Gynecologists has more on COVID-19, pregnancy, and breastfeeding.
SOURCES: Rita Carsetti, MD, Clinical Unit of Diagnostic Immunology, Bambino Gesù Children’s Hospital, Rome, Italy; Tina Tan, MD, professor of pediatrics, Northwestern University Feinberg School of Medicine, Chicago, and spokesperson, Infectious Diseases Society of America, Arlington, Va.; Lori Feldman-Winter, MD, MPH, professor, pediatrics, Rowan University Cooper Medical School, Camden, NJ; Open JAMA NetworkNovember 3, 2021, online