doi:10.1136/archdischild-2021-322463engBauerl, C..Randazzo, W.Sánchez, G.Selma-Royo, M.García Verdevio, E.Martínez, L.Parra-Llorca, A.Lerín, C.Fumadó, V.Crovetto, F.Crispi, F.Pérez-Cano, F. J.Rodríguez, G.Ruiz-Redondo, G.Campoy, C.Martínez-Costa, C.Collado, M. C. on behalf of MilkCORONA study teamSARS-CoV-2 RNA and antibody detection in breast milk from a prospective multicentre study in SpainART-2022-125742Objectives: To develop and validate a specific protocol for SARS-CoV-2 detection in breast milk matrix and to determine the impact of maternal SARS-CoV-2 infection on the presence, concentration and persistence of specific SARS-CoV-2 antibodies. Design and patients: This is a prospective, multicentre longitudinal study (April–December 2020) in 60 mothers with SARS-CoV-2 infection and/or who have recovered from COVID-19. A control group of 13 women before the pandemic were also included. Setting: Seven health centres from different provinces in Spain. Main outcome measures: Presence of SARS-CoV-2 RNA in breast milk, targeting the N1 region of the nucleocapsid gene and the envelope (E) gene; presence and levels of SARS-CoV-2-specific immunoglobulins (Igs)—IgA, IgG and IgM—in breast milk samples from patients with COVID-19. Results: All breast milk samples showed negative results for presence of SARS-CoV-2 RNA. We observed high intraindividual and interindividual variability in the antibody response to the receptor-binding domain of the SARS-CoV-2 spike protein for each of the three isotypes IgA, IgM and IgG. Main Protease (MPro) domain antibodies were also detected in milk. 82.9% (58 of 70) of milk samples were positive for at least one of the three antibody isotypes, with 52.9% of these positive for all three Igs. Positivity rate for IgA was relatively stable over time (65.2%–87.5%), whereas it raised continuously for IgG (from 47.8% for the first 10 days to 87.5% from day 41 up to day 206 post-PCR confirmation). Conclusions: Our study confirms the safety of breast feeding and highlights the relevance of virus-specific SARS-CoV-2 antibody transfer. This study provides crucial data to support official breastfeeding recommendations based on scientific evidence.2022http://zaguan.unizar.es/record/10958310.1136/archdischild-2021-322463http://zaguan.unizar.es/record/109583oai:zaguan.unizar.es:109583Archives of Disease in Childhood-Fetal and Neonatal Edition 107, 2 (2022), 217-221by-nchttp://creativecommons.org/licenses/by-nc/3.0/es/info:eu-repo/semantics/openAccess