Identified human breast milk compositions effectively inhibit SARS-CoV-2 and variants infection and replication

The global pandemic of COVID-19 caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection confers great threat to public health. Human breast milk is a complex nutritional composition to nourish infants and protect them from different kinds of infectious diseases including COVID-19. Here, we identified that lactoferrin (LF), mucin1 (MUC1), and alpha-lactalbumin (alpha-LA) fromhuman breastmilk inhibit SARS-CoV-2 infection using a SARS- CoV-2 pseudovirus system and transcription and replication-competent SARS-CoV-2 virus- likeparticles (trVLP). In addition, LF andMUC1 inhibitedmultiple steps including viral attachment, entry, and postentry replication, whereas alpha-LA inhibited viral attachment and entry. Importantly, LF, MUC1, and alpha-LA possess potent antiviral activities toward variants such as B.1.1.7 (alpha), B.1.351 (beta), P.1 (gamma), and B.1.617.1 (kappa). Taken together, our study provides evidence that human breast milk components (LF, MUC1, and alpha-LA) are promising antiviral and potential therapeutic candidates warranting further development for treating COVID-19.