Quantification and progress over time of specific antibodies against severe acute respiratory syndrome coronavirus 2 in breast milk of lactating women vaccinated with BNT162b2 Pfizer-BioNTech coronavirus disease 2019 vaccine (LacCOVID)

Esteve Palau, ErikaGonzalez-Cuevas, AraceliGuerrero, M. EugeniaGarcia-Terol, ClaraAlvarez, M. CarmenGarcía, GenevaMoreno, EncarnaMedina, Francesc-XavierCasadevall Aguilar, DavidDiaz-Brito, V.2022-11-302022-11-302022Esteve-Palau E, Gonzalez-Cuevas A, Guerrero ME, Garcia-Terol C, Alvarez MC, Garcia G, et al. Quantification and progress over time of specific antibodies against severe acute respiratory syndrome coronavirus 2 in breast milk of lactating women vaccinated with BNT162b2 Pfizer-BioNTech coronavirus disease 2019 vaccine (LacCOVID). Open Forum Infect Dis. 2022 May 11; 9(6): ofac239. DOI: 10.1093/ofid/ofac2392328-8957http://hdl.handle.net/10230/55042Background: several observational studies demonstrated the passage of postvaccine antibodies through breast milk in women vaccinated against coronavirus disease 2019 (COVID-19), mostly with messenger RNA (mRNA)-based vaccines, but lacked long-term data. Methods: a 6-month prospective cohort study was performed to determine severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine-induced antibody levels in the breast milk of 33 lactating healthcare workers at different timepoints after mRNA BNT162b2 Pfizer-BioNTech COVID-19 vaccination. Moreover, we examined the correlation of SARS-CoV-2 antibody levels between serum and breast milk, adverse events related to vaccination, and rate of SARS-CoV-2 infections. Results: mothers' median age was 38 (interquartile range [IQR], 36-39) years and 15 (IQR, 10-22) months for infants. Median (IQR) SARS-CoV-2 immunoglobulin G (IgG) spike protein subunit S1 (S1) vaccine-induced levels at different timepoints for serum-milk pairs were 519 (234-937) to 1 (0-2.9) arbitrary units (AU)/mL at 2 weeks after first dose and 18 644 (9923-29 264) to 78 (33.7-128), 12 478 (6870-20 801) to 50.4 (24.3-104), 4094 (2413-8480) to 19.9 (10.8-51.9), 1350 (831-2298) to 8.9 (7.8-31.5) AU/mL at 2, 4, 12 and 24 weeks after second dose, respectively. We observed a positive correlation of antibody levels between serum and breast milk, no serious adverse events related to vaccination, and 2 (6%) COVID-19 vaccine breakthrough infections. Conclusions: women vaccinated with Pfizer-BioNTech transmit antibodies into breast milk with a positive correlation with serum levels. Both decreased over time in a 6-month follow-up.application/pdfengCopyright © Esteve-Palau E, Gonzalez-Cuevas A, Guerrero ME, Garcia-Terol C, Alvarez MC, Garcia G, et al. 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.Quantification and progress over time of specific antibodies against severe acute respiratory syndrome coronavirus 2 in breast milk of lactating women vaccinated with BNT162b2 Pfizer-BioNTech coronavirus disease 2019 vaccine (LacCOVID)info:eu-repo/semantics/articlehttp://dx.doi.org/10.1093/ofid/ofac239COVID-19SARS-CoV-2BreastfeedingmRNA-based vaccinationPassive immunityinfo:eu-repo/semantics/openAccess