...or caused the infection for all you know.
Very hard to avoid infection after spending several hours in cancer clinic waiting in reception room and then long discussion with wife’s Oncologist and then drive her to hospital for tests.
Even the most successful vaccine ever, which eradicated the disease from the globe, did not prevent me from getting infected with smallpox, which has mortality of 30%+. But I recovered in a week with help from vaccine created anti-bodies.
May be one day they will create a vaccine which can build a virus proof filter in the respiratory system. Bot there yet.