COVID-19 mRNA vaccine and antibody response in lactating women: a prospective cohort study.

Centro Hospitalar Universitário de Lisboa Central (CHULC), Lisboa, Portugal. nadia.b.charepe@edu.nms.unl.pt. Comprehensive Health Research Centre, NOVA Medical School, Universidade NOVA de Lisboa, Lisboa, Portugal. nadia.b.charepe@edu.nms.unl.pt. Human Immunobiology and Pathogenesis Laboratory, Lisbon, Portugal. CEDOC-Chronic Diseases Research Center NOVA Medical School | Faculdade de Ciências Médicas, NOVA University of Lisbon, Lisbon, Portugal. Comprehensive Health Research Centre, NOVA Medical School, Universidade NOVA de Lisboa, Lisboa, Portugal. EpiDoC Unit, CEDOC, NOVA Medical School, Universidade NOVA de Lisboa, Lisboa, Portugal. Centro Hospitalar Universitário de Lisboa Central (CHULC), Lisboa, Portugal.

BMC pregnancy and childbirth. 2021;(1):632
Full text from:

Abstract

BACKGROUND Immunological protection via breastfeeding is well known. The immunological profile of human milk changes during lactation. No clinical trials have been conducted in lactating women with the newest mRNA vaccines against SARS- CoV-2. A Few studies have shown the presence of antibodies in breastmilk after vaccination. The aim of this work is to study possible antibodies transfer via breastmilk and also the immunological characteristics of lactating women compared to non-lactating women, after using the BNT162b2 Pfizer vaccine. METHODS This is a prospective cohort study with a convenience homogenous sample of 24 healthcare workers (14 lactating and 10 non-lactating women) enrolled at the time of COVID-19 vaccination. Clinical data was registered in a questionnaire. Titers of SARS-CoV-2 spike IgG, IgA and IgM were quantified in post vaccination blood and human milk. Antibody quantification was performed by an in-house ELISA to SARS-CoV-2 trimeric spike protein. RESULTS All women showed immunity after vaccination with positive antibodies for IgM, IgA and IgG antibodies. The dominant serum antibody response was IgG. Modest levels of antibodies in breastmilk of lactating mothers were observed in this study, especially IgG in 42.9%. There was a moderate association between higher titers of IgG and a longer duration of breastfeeding (R= 0.55, p=0.041). CONCLUSIONS Evidence of antibody transfer in human milk after COVID-19 vaccination is scarce. The presence of antibodies in human milk is reported, but immunization through breastfeeding is still to be established.

Methodological quality

Publication Type : Clinical Trial

Metadata