Qualitative immunoassay for the detection of anti-SARS-COV-2 spike antibody in human milk samples

Antibodies in milk obtained from those previously SARS-CoV-2-infected or vaccinated against COVID-19 may provide passive immunity to the breastfed infant. Few assays have been established to measure antibodies in human milk, despite the public health importance of this topic. In the present protocol, we describe an optimized indirect ELISA assay aimed to measure SARS-CoV-2-reactive antibodies in human milk, which can be used as a rapid screen on undiluted samples or to designate samples as relatively low, moderate, or high titer. For complete details on the use and execution of this protocol, please refer to Fox et al. (2020).