A vaccine made of recombinant outer surface proteins from Borrelia burgdorferi (CDC1999). Since the last update, we have not found any published data on its excretion in breast milk. Its very high molecular weight makes its transfer to milk in significant quantities very unlikely.Its low oral bioavailability would hinder its transfer to the infant’s plasma from ingested breast milk because, due to its protein nature, it degrades in the gastrointestinal tract, and is not absorbed. This vaccine was withdrawn from sale in 2002, after only a few years of availability (FDA 2002) for reasons unrelated to its effectiveness (Kaaijk 2016, Aronowitz 2012). Vaccines are compatible with breastfeeding, both those that are live attenuated microorganisms, as well as those that are dead, inactivated or those formed by parts of or toxoids of the same (Sachs 2013, CDC 2011).With the exception of rubella, smallpox and yellow fever, live virus vaccines are not excreted in breast milk and do not cause problems in infants, except for yellow fever in children under 6 months (Sachs 2013, CDC 2011).Breastfeeding can improve the antibody response of vaccines (CDC 2011).Women who breastfeed can and should be protected with the recommended vaccines like other adults.