Breastfeeding and immunity

How breastfeeding helps support and develop a baby’s immune system

It is well known that breastfed babies are less likely to get infections than are formula-fed babies. Breastmilk contains many factors that help to support a baby’s immune system. A mother passes on lots of proteins, fats, sugars and cells that work against infections when she breastfeeds her baby (eg antibodies, white blood cells, lactoferrin, lysozyme, oligosaccharides, probiotics and prebiotics).

When a mother comes into contact with germs in her environment, she makes antibodies to fight those germs. These antibodies pass into the breastmilk and therefore into the baby. Since a mother and her baby are generally in contact with the same germs, this helps to protect her baby from the illnesses they are both exposed to. The main type of antibody in breastmilk is IgA. IgA antibodies protect the internal surfaces of the body, such as the mouth, stomach, intestines and lungs. They are not digested by the baby, they just coat the gut and block the entry of infections that could otherwise cause illness.

In addition, there are a number of other factors in breastmilk that help a breastfed baby develop a more efficient immune system. For example, breastfed babies tend to have a larger thymus gland than those fed infant formula. The thymus gland makes a type of white blood cell that helps protect against infections.

Breastfeeding and immunisation

The Australian Breastfeeding Association’s position statement on breastfeeding states: ‘Breastfeeding alone does not provide sufficient immunity to childhood diseases and parents need to seek appropriate guidance on immunisation from their medical advisers’.

Although breastfeeding often reduces the severity of illness in a baby, it is important to understand that breastfeeding does not provide a substitute for immunisation. In other words, breastfeeding does not provide total immunity to your baby to vaccine-preventable diseases. Vaccines developed against severe, life-threatening diseases—polio, diphtheria, measles and others— are another important way to protect our children’s health. Breastfeeding may improve a baby’s response to some immunisations. When breastfed babies are vaccinated, they produce higher levels of antibodies in response to some vaccinations compared to formula-fed babies.

Breastfeeding and vaccination

In general, it is safe for breastfeeding women to receive a vaccination should it be needed – however, each mum should check with her health care provider for specific information on each vaccination. For more information see The Australian Immunisation Handbook (2013).

Vaccine recommendations for babies are consistent regardless of whether a baby is breastfed or not. For more information see The Australian Immunisation Handbook.

Breastfeeding is known to be an effective distraction from pain in babies. Mothers find it helpful to breastfeed while their baby receives a vaccination to reduce their baby’s pain perception.


Australian Government, Department of Health and Ageing 2013, The Australian Immunisation Handbook. 10th edn. Accessed 13/6/13 from URL:

Hanson L 2004, Immunobiology of Human Milk: How Breastfeeding Protects Babies. Pharmasoft Publishing: Göteborg Sweden.

State Government of Victoria, Department of Health 2012, Immunisation and pregnancy. Accessed 13/6/13 from URL:

Tansky C, Lindberg CE 2010, Breastfeeding as a pain intervention when immunizing Infants. Journal for Nurse Practitioners 6(4):287-295.

© Australian Breastfeeding Association June 2013

The information on this website does not replace advice from your health care providers.

Last reviewed: 
Jun 2016