How do I know "her experience is entirely consistent with Omicron appearing less virulent because it's infecting the previously infected and vaccinated who alre

How do I know "her experience is entirely consistent with Omicron appearing less virulent because it's infecting the previously infected and vaccinated who already have some degree of immunity." 1. We know that break through infections are less serious than infections to the unvaccinated and uninfected. 2. We determine virulence by # of hospitalizations (or other serious outcome) / # of infections 3. If we add more infections that don't have serious outcomes (because they are break through cases) that greatly increases the denominator without affecting the numerator. 4. This is how you could have Omicron be just as virulent as the original but look less virulent to a doctor. (Because of the break through cases) Does that make sense?