My sister in law tested positive for COVID yesterday but lives alone. She has only been to the supermarket and out for walks alone in the past few weeks. Trying to work out how on earth str could have caught it! We did see her about ten days ago but we are a family of five and none of us have had any symptoms. We have also been in school/seen other family members who are older and none of them have symptoms. I would have thought if it was us, someone somewhere would have had symptoms from our wider circle. How on earth could she have caught it at a supermarket or on a walk?