Breastfeeding women/lactating individuals were not included in vaccine clinical trials for Pfizer or Moderna COVID-19 vaccines, so there is no breastfeeding-specific data available. Based on the information that does exist and according to a statement from the Academy of Breastfeeding Medicine, there is little potential riskfor mom or baby, and possible benefit to the breastfed baby as antibodies against the virus may be passed through breastmilk.
Pfizer and Moderna COVID-19 vaccines are not live virus vaccines. Therefore they are not capable of infecting the recipient with COVID.
Pfizer and Moderna vaccines are mRNA vaccines. The mRNA carries a code for a protein, the SARS-CoV-2 spike protein. It is injected into and taken up by the muscle cells, and tells the body to produce the protein. The spike protein stimulates an immune response, which protects the recipient from the virus.
Breastfeeding moms and lactating individuals were excluded from clinical trials for Pfizer and Moderna vaccines so there is no specific data. Based on the information available, there is little potential for harm.
The CDC states that, with the exception of vaccines for small pox and yellow fever, vaccines are safe while breastfeeding.
Because the vaccine is injected into and taken up by muscle cells, it is actually unlikely that any of the particles would enter into the bloodstream or breast milk. If any of the components do make their way into breast milk, experts expect these to be digested by the baby.
With other vaccinations, antibodies were found in breast milk within 5-7 days post vaccination. Based on this information, it is expected that the antibodies created against the virus in response to the vaccine will be passed through breast milk, offering passive immunity to your baby.
It is not recommended to discontinue or interrupt breastfeeding after receiving the vaccine.
https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/pregnancy.html
https://www.bfmed.org/abm-statement-considerations-for-covid-19-vaccination-in-lactation