COVID-19 mRNA vaccine is not detected in human milk

Several countries have recently approved the use of mRNA vaccines against COVID-19 under an emergency use authorization. However, no pregnant or lactating individuals were included in the Phase 3 clinical trials of these vaccines despite belonging to a group at high risk for severe complications of COVID-19 infection. We show here that the mRNA from anti-COVID BNT162b2 (Pfizer) and mRNA-1273 (Moderna) vaccines is not detected in human breast milk samples collected 4-48 hours post-vaccine. These results strengthen the recommendation of ABM and WHO that lactating individuals who receive the anti-COVID-19 mRNA-based vaccine should continue to breastfeed their infants uninterrupted.