What would happen if a single coronavirus entered our body? Probably nothing. An infection is like an invasion, and to be successful you need a minimal amount of soldiers. Many? Depends. The so-called infectious dose (not to be confused with “viral load“) is defined as the “Estimated number of organisms or viruses required to produce an infection in 50% of exposed adults“, although sometimes it refers to the minimum figure necessary. It is a quantification that, after a year of pandemic, remains unknown for the SARS-CoV-2 that causes COVID-19.