Flu shots are one of the best protections against getting the flu. It is a seasonal vaccine that is routinely distributed each year. October or November is recommended as one of the best times to get vaccinated, but as the influenza season occurs in January and sometimes even later so getting vaccinated in December or later can still be beneficial. It takes around 14 days to develop immunity after the injection and immunity lasts for approximately 90 days. For more information visit: http://www.cdc.gov/flu/