A: Breastfeeding can likely help protect babies from COVID-19 but we don’t know yet how well.
Antibodies from vaccination or infection are transferred through breast milk, but they are short-lived and do not enter the bloodstream. By contrast, antibodies transferred during pregnancy enter the fetal bloodstream, where they often persist for six months or more, and ARE proven to protect infants from hospitalizations associated with COVID-19 .
🍼 Antibodies usually start to show up in breast milk a few weeks after vaccination or infection. The main type of antibody transferred through breast milk is the “secretory” type called IgA, but other types (IgM and IgG) can also be transferred. These antibodies linger in the upper respiratory tract and gut, but do not enter the bloodstream. We don’t have data (yet) on the level of protection offered by these antibodies, but studies are underway.
🤷🏽♀️ Antibody types and levels in breast milk differs greatly from person to person, over time, and between vaccination versus infection. This variation can make it hard to predict exactly what you pass on to your baby.
🚫 While breast milk can transfer antibodies, it does not transfer vaccines or infectious viral particles. A recent study of 110 lactating women infected with COVID-19 found no evidence of infectious viral particles in breast milk. Earlier studies have shown that mRNA vaccines are not transmitted through breast milk.
🤰Pregnancy presents a unique opportunity to share long-lasting, powerful antibodies through the placenta. These antibodies enter the fetal bloodstream and persist in babies for up to 6 months or longer. One recent study found that 98% of babies had detectable anti-Spike IgG antibodies following maternal vaccination. Several studies have now shown dramatically better health outcomes in both parents and babies after vaccination.
✨ Vaccination against COVID-19 during pregnancy is strongly recommended by relevant expert bodies like the American College of Obstetricians and Gynecologists.✨
The Bottom Line
➡️ Breastfeeding likely offers your baby some protection against COVID-19 (if you have antibodies from previous infection or vaccination), but the level of protection is uncertain and transient.
➡️ To best protect your little ones, keep using layers of protection for the whole family including your #SMARTS, vaccination during pregnancy, and breastfeeding when possible.
Once I’m vaccinated, can I pass on the antibodies to my baby by breastfeeding?
Great background post on antibodies in pregnancy and lactation (Unambiguous Science)
The American College of Obstetricians and Gynecologists (ACOG) resources
Association of Human Milk Antibody Induction, Persistence, and Neutralizing Capacity With SARS-CoV-2 Infection vs mRNA Vaccination
No infectious SARS-CoV-2 in breast milk from a cohort of 110 lactating women
Durability of Anti-Spike Antibodies in Infants After Maternal COVID-19 Vaccination or Natural Infection