3 ms·

Does lethality after the contagious period matter? Doesn't seem that there would be any selective pressure if the host (and its extant, too lethal viruses) per

• foota 6y ago
  No, it wouldn't. I'm not an expert in epidemiology, so take what I'm about to say as speculation. My understanding is that viruses typically cause symptoms because they cause the virus to spread, things like coughing spread the virus. If a virus induces too strong of a reaction then the host dies or can't function while they have it and it doesn't spread. It's probably unlikely for a virus to develop an infectious period where the symptoms are mild but strong enough to spread and then shift phases to become lethal, as a virus has no coordination between itself. I think typically viruses are either in an asymptomatic phase, where they're less likely to spread and don't cause symptoms (because they haven't replicated much), and a symptomatic phase where spreading is more likely but obvious the person has it. As a last bit, my understanding is that "novel" viruses, such as this novel coronavirus, are particularly concerning when they cross over from a non human host and become infectious because they haven't developed to have mild symptoms that are amenable to spreading well, and so can be more deadly than viruses that evolved alongside or within the human population.