“She warns that flu shots work by getting the bodys immune system to produce antibodies to particular pressures of the influenza virus, “and it takes about two weeks after getting a flu vaccine for your body to have a complete reaction.”Joshi says everyone needs to get the influenza vaccine (with unusual exceptions), and individuals who are high risk– those 65 and older, the very young and those with persistent conditions or weakened immune systems– are also at high risk of influenza complications.”Teachers, first responders, those who travel for work or are in close distance to someone at high risk for a flu complication must also make sure to get the influenza shot,” she says.The CDC warns that although vaccines must be administered by the end of October, even if you miss out on that deadline, you must still get vaccinated for as long as influenza viruses are circulating locally.Tell us your coronavirus stories, whether its a news tip, a topic you desire us to cover, or an individual story you desire to share.Our journalism requires your support.