Viruses generally become milder because of selective pressure to do so. If it kills the host, it doesn't get to spread as much. Plus, of you get slightly sick

Viruses generally become milder because of selective pressure to do so. If it kills the host, it doesn't get to spread as much. Plus, of you get slightly sick, you probably continue your life and infect others. If you get horridly sick, you stay in bed and encounter no one. WWI made the Spanish Flu have it's second wave. Mildly I'll soldiers stayed where they were. Really sick ones were sent in overcrowded trains far from the front lines back to overflowing hospitals with inadequate sanitation. These lockdowns we are doing are encouraging a deadly second wave.