Take the swine flu shot agian?

If you already took the swine flu shot then do you need to take it agian?

I took the shot already, the nazal spray type where you spray the liquid down your nose. do i need to take it again because i took that like 4 or 5 months ago. is there a certain time amount where you have to get the shot agian?

sorry if it is a little confusinhg.. i tried.. o.o