ACE2 and infection: The use of lactoferrin supplementation as an add-on to the standard-of-care therapy in treating COVID-19 has been hypothesized based on several in vitro evidences, supporting its ability to inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication [25,146,157] as well as its interaction with angiotensin-converting enzyme 2 (ACE2—the main entry receptor leading to host’s cells infection) [146,160], thus contrasting the very early infection stages.