Breastfeeding helps support and develop your baby’s immune system.
Breastfed babies are less likely to get infections than formula-fed babies. Breastmilk contains many parts that work together to help protect your baby.
When you breastfeed, your baby receives lots of proteins, fats, sugars and cells that work against infections. The cells include antibodies, white blood cells, lactoferrin, lysozyme, oligosaccharides, probiotics and prebiotics.
Together, these help protect your baby from germs and reduce the chance of illness.
How you pass protection to your baby
When you come into contact with germs, your body makes antibodies to fight them. These antibodies pass into your breastmilk and then to your baby.
Because you and your baby usually share the same environment, this helps protect your baby from the illnesses around you both.
Antibodies in breastmilk
The main antibody in breastmilk is called IgA.
IgA helps protect parts of your baby’s body such as the mouth, stomach, intestines and lungs.
These antibodies aren’t broken down in your baby’s tummy. Instead, they coat the baby’s gut and help block infections from getting in.
Other ways breastmilk supports immunity
Breastmilk supports more than just short-term protection. It also helps your baby’s immune system develop and work efficiently. For example, breastfed babies tend to have a larger thymus gland (a small gland in the chest). This gland helps make white blood cells that fight infection.
Breastfeeding and vaccinations
Vaccinations for mum
If you’re breastfeeding, it’s generally safe to have vaccinations if you need them. If you’re unsure about a vaccine, you could talk with your healthcare provider.
Vaccinations for baby
Babies need the same vaccinations whether they’re breastfed or formula-fed.
Breastfeeding can help reduce the severity of illness in your baby, but it doesn’t replace immunisation. It’s important to follow the recommended vaccination schedule to help protect your baby from serious diseases. For more information, see The Australian Immunisation Handbook.
Breastfeeding may also support how your baby responds to some vaccines. Breastfed babies tend to produce higher levels of antibodies after some vaccinations.
Breastfeeding during vaccinations
Breastfeeding can help comfort your baby during vaccinations. Feeding before or during an injection can reduce pain and distress for many babies.1
© Australian Breastfeeding Association May 2026
- Harrison D, Reszel J, Bueno M, Sampson M, Shah VS, Taddio A, Larocque C, Turner L. Breastfeeding for procedural pain in infants beyond the neonatal period. Cochrane Database of Systematic Reviews 2016, Issue 10. Art. No.: CD011248. https://doi.org/10.1002/14651858.CD011248.pub2.
