I live out in the countryside in England near a village of 600 people. We had a meeting this evening to organise ourselves. About thirty volunteers have been given about ten houses each, next to their homes to check on the welfare of the occupants. This means that everyone including the elderly and infirm are visited a minimum of once a week, the vulnerable more frequently, to see if anyone is lacking in food or transport. This way, should anyone who gets sick or worse still, contracts the Covid 19 virus it will quickly become apparent and measures can be immediately taken.
The same idea will work in urban areas, it requires local volunteers and a list of those willing to help out in emergencies or do shopping for others etc and a street or block coordinator.
Our village has a facebook page which connects people and gives local news and alerts.