A woman who is breastfeeding can be immunised safely with vaccines such as tetanus, diphtheria and whooping cough (Tdap), COVID-19, hepatitis B, human papillomavirus (HPV), influenza, MMR (measles, mumps and rubella), and chickenpox (varicella) vaccines. Woman can continue to breastfeed after they receive their immunisation. There are no safety concerns for the woman or her baby or child.

Inactivated and subunit vaccines such as the Tdap, hepatitis B, HPV, and influenza vaccines use inactivated viruses, and/or non- living proteins, sugars or nucleic-acid components (antigens) to teach the immune system. After the vaccine is administered the immune system recognises the antigens immediately and responds locally.

The viruses in the measles, mumps, and rubella (MMR) and chickenpox vaccines are alive but weakened so they can replicate in the body without causing the disease. After the vaccine is administered, these viruses make more of themselves (replicate) until there are enough for the immune system to recognise and respond to.

The measles, mumps, and varicella vaccine viruses have not been found in breast milk after maternal immunisation. The rubella vaccine virus has been found in breast milk. However, no symptomatic cases of vaccine-related rubella have been identified in breastfed babies whose mother received a rubella containing vaccine. This group of babies have also been shown to have a normal immune response to a rubella containing vaccine in their second year of life.

Protective cells produced by the breastfeeding woman in response to immunisation may be secreted in breast milk. The type and quantity of these antibodies, and whether they provide any protection for the baby after they are swallowed, are dependent on the vaccine received and maternal factors that influence immune system function such as genes, age and health. Maternal antibodies in breast milk have not been shown to reduce the infant’s response to their own immunisations. However, some studies suggest that breast milk may improve an infant’s immune response to some of the immunisations they receive.

The best way to give young babies some protection against whooping cough and influenza while they are too young to be fully immunised themselves is by giving vaccines to the mother during her pregnancy. Receiving the vaccine stimulates the mother’s immune system to make protective cells (antibodies) that circulate in her blood stream and travel across the placenta into her baby’s blood stream and help protect the baby from severe whooping cough for up to three months and influenza for up to six months after birth.

After her baby has been born, it is important that a woman continue to receive age-appropriate catch-up vaccines during the postnatal period for protection against diseases such as tetanus, measles, mumps, rubella, and HPV. Women who did not receive the Tdap or influenza vaccines during pregnancy can have them after baby has been born to reduce the risk of exposing her baby to whooping cough or influenza.

After her baby receives their routine immunisations, including the rotavirus vaccine, a woman can continue her usual breastfeeding routine. A baby can breastfeed immediately after receiving their rotavirus vaccine dose, even if the mother has cracked nipples. No special precautions need to be taken by the mother.

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