You can't play good chess if you have a cold or flu. To be a good player you need to maintain your health. To avoid colds and flu don't fly to the doctor and get flu shots or Tamifly or whatever, the last time I went to the doctor he flew away with my money and left me with the flu. Instead use garlic. I have been telling this to people for years and years and now Dr. Mercola has published information about this on his website: http://articles.mercola.com/sites/articles/archive/2013/02/04/zinc-garlic-vitamin-d.aspx?e_cid=20130204_DNL_art_1&utm_source=dnl&utm_medium=email&utm_campaign=20130204
There is no real evidence that flu shots work nor is there evidence that Tamiflu is any good but there is now statistical evidence that garlic stops and ameliorates colds and flu.
I, too, am a doctor, a D.D, not an M.D. but you can take the word of 2 doctors, take lots of garlic to stay healthy.