From the Guidelines
Measles vaccination of a breastfeeding mother does not provide significant protection to her infant through passive immunity. While some antibodies from the mother's immune response to vaccination can transfer into breast milk, this mechanism does not provide reliable or complete protection against measles for the infant. The primary way infants receive passive immunity against measles is through maternal antibodies transferred across the placenta during pregnancy, not through breastfeeding after vaccination.
Key Points
- Breastfeeding does not adversely affect immunization and is not a contraindication for any vaccine, as stated by the Advisory Committee on Immunization Practices (ACIP) 1.
- For proper protection, infants should receive their own measles vaccination according to the recommended schedule, typically with the first dose of MMR (measles, mumps, rubella) vaccine at 12-15 months of age.
- In high-risk situations or during outbreaks, infants as young as 6 months may receive an early dose, though they will still need the regularly scheduled doses later, as recommended by the ACIP 1.
- This recommendation exists because the passive immunity an infant receives before birth gradually wanes over the first year of life, leaving them vulnerable to infection.
- While breastfeeding offers many immune benefits to infants, it cannot substitute for direct vaccination when it comes to measles protection.
Considerations
- The ACIP recommends that breast-fed infants should be vaccinated according to routine recommended schedules 1.
- The use of immune globulin (IG) may be preferred for infants aged less than 12 months who are household contacts of measles patients, as it provides immediate protection against measles 1.
From the Research
Measles Vaccination and Breastfeeding
- Measles vaccination of a breastfeeding mother does not directly protect the infant via passive immunity, as the vaccine-induced antibodies are not transferred to the infant through breast milk in significant amounts 2.
- However, breastfeeding has been shown to have a modest protective effect against measles infection in infants, independent of measles vaccination 3.
- The protection afforded by breastfeeding is thought to be due to the transfer of maternal antibodies to the infant through colostrum and breast milk, although the levels of these antibodies decline rapidly after birth 2.
Maternal Antibody Waning
- Maternal antibodies against measles wane rapidly in infants, with most losing protective levels by 4-6 months of age 4, 2.
- This leaves a susceptibility gap between the waning of maternal antibodies and the age at which infants are typically vaccinated against measles 4.
- The rate of waning of maternal antibodies can vary depending on factors such as the level of maternal immunity and the age at which the infant is born 2.
Vaccination Strategies
- The optimal age for measles vaccination is typically considered to be around 9-12 months, although this may vary depending on the specific epidemiological context and vaccination strategies in place 5, 6.
- In settings with high measles transmission or outbreaks, an additional dose of measles vaccine may be recommended at 6 months of age to provide earlier protection to young infants 5.