The weaker the virus, the less symptoms it has. If people who feel sick stay home, it gives less aggressive stains the chance to infect more people. On the oth

The weaker the virus, the less symptoms it has. If people who feel sick stay home, it gives less aggressive stains the chance to infect more people. On the other hand if infected people with strong symptoms infect others in hospitals, the opposit happens (that's how the Spanish flu first got more deadly).