You could better start taking vitamin D3 supplements. Some use 125 mcg(5000 Intl Units) daily in a tiny gelcap, others take less, still others more. It is much netter protection against flu(and colds) than anything in a needle and the microbes do NOT develop any immunity to it. It is cheaper and makes no complications. Or you could move to a tropical or subtropical land and get out in the sunshine every day. The D3 is a less traumatic solution and avoids the air fare.
I take The D3, Quercetin NAC and zinc along with a drink which has whey protein powder. The last is jam-packed with lactoferrin which is an antiviral milk protein.
There is probably better science behind the above than there is in this ridiculous flu shot