Careful of the flu shot - worst case ever two years ago when our family all took part, one had the flu three times between June and November, everyone got it at least once. Since then no flu shots and only one family member caught a cold this year. We also changed our lifestyle a bit.
Unfortunately the best remedy we have come across is to not mix with the community - I know, sounds funny but we avoid clubs, closed areas of any sort, shopping is done quickly and when out for dining it's alfresco no matter how cold, lucky we don't need nor use public transport but we drive if we do go somewhere. Neighbours are ok at a distance and if anyone can do it then work from home ---- sounds terrible I know but that's the way it is.
