On December 20, 2020, Israel initiated a national vaccination program against COVID-19. One prioritized group was health care workers, many of whom are breastfeeding women. Despite the fact that the vaccine trial did not include this population and no other vaccine-related safety data had been published, breastfeeding women belonging to risk groups were encouraged to receive the vaccine. The Centers for Disease Control and Prevention has also recommended that breastfeeding women belonging to vaccine-target groups be immunized. We investigated whether maternal immunization results in secretion of SARS-CoV-2 antibodies into breast milk and evaluated any potential adverse events among women and their infants.