When is it justified to isolate (not talking about the lock down) for covid-19? which symptoms justifies it?

Any contagiousness: A person with any signs of respiratory infection or gastrointestinal infection should be isolated to prevent spread of his infection. Allergies can cause symptoms similar to infection symptoms, which means a person with allergy symptoms at this pandemic time should also be isolated. Note that if every person is isolated for 3-4 weeks, the pandemic stops because virus transmission stops. (3/25/20)

Stay at Home: If you have had contact with someone who has or may have COVID 19. There are a variety of symptoms to include dry cough, shortness of breath, nasal congestion, fever, headache, sore throat, feeling tired, loss of sense of taste/smell, decreased appetite, nausea, diarrhea, vomiting, chills without or without shaking & muscle aches. Don't infect others regardless of what infectious disease you hav