It is, in fact, clear cut. Virulence refers only to the degree of damage done. [0] There are several interrelated terms, which you conflated in your previous c

It is, in fact, clear cut. Virulence refers only to the degree of damage done. [0] There are several interrelated terms, which you conflated in your previous comment. It's important for all of us to have the right mental model about how these fit together, so I'm going to press on this point. - Transmissibility: how easily a pathogen travels from one organism (vector or host) to another - Infectivity: how easily a pathogen can establish infection in a host - Pathogenicity: degree of ability to cause disease in host - Virulence: degree of damage done to host - Virulence factors: factors that, in aggregate, can affect virulence Virulence is affected by virulence factors, but these are not equivalent to virulence, and increasing a virulence factor does not necessarily mean that virulence will go up. (Another way of saying this: Taken individually, virulence factors are necessary but not sufficient for the definition or measurement of virulence.) So of course, if a pathogen has higher transmissibility or infectivity, it has a greater potential for virulence. At the same time, that does not mean it is actually more virulent. So taken in the context of your comment, the clearest word to use is almost certainly transmissibility or infectivity, depending on the data you're referring to. [0]: https://www.biologyonline.com/dictionary/virulence https://www.biologyonline.com/dictionary/virulence