How can ventilation be improved to protect against COVID; post-op lung complications in patients who isolated before surgery; what's it like living with tinnitus?; and calls to do more to prevent chronic disease

How can ventilation be improved to help reduce the spread of COVID?

The surprising discovery that patients who isolate prior to surgery are more likely to develop post-operative lung complications.

What's it like living with tinnitus and can anything be done about it?

And calls to do more to prevent chronic disease.