Your sentence does not make much sense, but I think I figure out what you are trying to say.
Some people do have a bad reaction to the flu shot, it is usually those people who have an allergy to eggs. Before you are offered a flu shot, the medic doing it will ask if you have a cold or feeling unwell and whether you have an allergy to eggs. If so, you would not be given the shot at that time until you are well. In the case of an allergy to eggs, you would not be given the shot at all.
In the UK, since the flu shot always now includes the anti swine flu med, personally I refuse to have it now.
The flu shot is offered to people who are at risk of getting the flu and the immunization does not cover all strains of the virus. The flu viruses do change and that is why the vaccine is offered every year to those people and children with low immunity.
The word that makes no sense is "hart."
I think you were meant to write "hurt" and not "hart" - is that right?
Having a flu shot should only feel like a pin prick. Best thing to do when having a flu shot is to rub the area where the needle went in. This will help to disperse the vaccination.