15 Antibodies in breast milk inhibited newborns’ seroconversion following polio immunization. 16 This effect was temporary and it was considered unnecessary to withhold breastfeeding when administering oral polio vaccines to infants >6 weeks of age. 17 Moreover, antibody response following rubella vaccine in breastfed infants whose mothers received rubella vaccine postpartum was similar to those in formula-fed infants and infants of naturally immune mothers. 18 Hence, immunization

with rubella in breastfeeding women does not Palbociclib cell line suppress the immune response to rubella vaccine in the infant. Antibody persistence in breast milk may vary depending on antibody type. Women vaccinated during pregnancy with pneumococcal and meningococcal

polysaccharide vaccines had specific IgA type 6B antibodies in colostrum that fell to undetectable levels by 2 weeks, whereas type 19F antibodies were found in breast milk up to 5 months. 19 Because an insignificant amount of antibodies in breast milk pass from the GI tract into infant circulation, these antibodies do not suppress the infant immune response. 20,21 CHIR-99021 in vivo Preservatives and other components of vaccines have caused concern over their potential effect on infants. Studies have assessed the effect of vaccine components (adjuvants, chemicals, preservatives, and additives) on infants, particularly that of thimerosol. Research has repeatedly refuted the association of adverse effects from thimerosol in vaccines administered directly to infants, 22 and the minute amounts that may possibly pass through breast milk should further reduce concern. Unfortunately, such concerns may lead to interruption of breastfeeding when the mother is immunized. The common Food and Drug Administration label “because many drugs are excreted

in human milk, caution should be exercised when administering vaccine Morin Hydrate to a nursing woman” does little to reassure. Nonetheless, with the exception of smallpox vaccine, breastfeeding is not a contraindication to vaccination (Table 1). Drugs that breastfeeding travelers may encounter include anti-infectives, antimalarials, high-altitude medications, analgesics, antimotility drugs, and topical preparations. The following section will review available data regarding their safety in breastfeeding infants. The most commonly prescribed anti-infectives in the pre-travel consultation are quinolones, macrolides, and occasionally sulfonamides, usually for self-treatment of travelers’ diarrhea. Doxycycline, a tetracycline prescribed for chemoprophylaxis of malaria, is also frequently considered in the United States but the World Health Organization (WHO) considers it contraindicated for prophylaxis and treatment for breastfeeding women.