Presenter of 1 Presentation
CODOMINANT IGG AND IGA EXPRESSION WITH MINIMAL VACCINE MRNA IN MILK OF BNT162B2 VACCINEES
Abstract
Background
Lactating women can produce protective antibodies in their milk after vaccination, which has informed antenatal vaccination programs for diseases such as influenza and pertussis. However, whether SARS-CoV-2-specific antibodies are produced in human milk as a result of COVID-19 vaccination is still unclear.
Aims
Our aims are (1) to longitudinally quantify SARS-CoV-2-specific IgA and IgG in human milk of lactating women who received COVID-19 mRNA vaccine, with reference to a cohort convalescent from antenatal COVID-19 as well as a control cohort of healthy lactating women, and (2) to detect and quantify vaccine mRNA in human milk after vaccination.
Methods
Prospective cohort study of a convenience sample of lactating healthcare workers living in Singapore, who were due to receive two doses of the BNT162b2 (Pfizer/BioNtech) vaccine/ We collected milk samples at 5 time points.
Results
Lactating mothers who received the BNT162b2 vaccine secreted SARS-CoV-2-specific IgA and IgG antibodies into milk, with the most significant increase at 3–7 days post-dose 2. Virus-specific IgG titers were stable out to 4–6 weeks after dose 2. In contrast, SARS-CoV-2-specific IgA levels showed substantial decay. Vaccine mRNA was detected in few milk samples (maximum of 2 ng/ml), indicative of minimal transfer. Infants who consumed post-vaccination human milk had no reported adverse effects up to 28 days post-ingestion.
Conclusions
Our results define the safety and efficacy profiles of the vaccine in this demographic and provide initial evidence for protective immunity conferred by milk-borne SARS-CoV-2-specific antibodies. Taken together, our study supports recommendations for uninterrupted breastfeeding subsequent to mRNA vaccination against COVID-19.