Figure S1. Antibody titers against SARS-CoV-2 spike protein in paired serum samples (1:50 dilution).

IgG and IgA titers in the serum samples were measured by ELISA (31). Similar results were also observed for the SARS-CoV-2 nucleocapsid protein with only the serum+/+ sample showing the presence of SARS-CoV-2 nucleocapsid protein-specific antibodies. Legend: Serum+/+ was the human milk sample from a SARS-CoV-2 PCR positive mother with SARS-CoV-2 spike specific IgA and IgG in serum and human milk. Serum+/− was the human milk sample from a SARS-CoV-2 PCR positive mother without SARS-CoV-2 spike specific antibodies in serum and human milk. Serum−/− was the human milk sample from a mother negative for SARS-CoV-2 and negative for SARS-CoV-2 spike specific antibodies in serum and human milk. Data information: Data are presented as mean.