http://www.bbc.co.uk/news/health-36105275
For people who get flu jabs, it looks as if they provide more immunity if the jab is done in the morning rather than the afternoon.
Tests done show that for 2 of the 3 strains of flu used in the vaccine more antibodies were produced for people who had the jab between 9am to 11am compared to those between 1pm and 5pm. The other strain showed the same level of antibodies.