If you have a flu jab each year

[ShoppingDays]

If you have a flu jab each year and some of the strains are the same as the previous year (and haven't mutated), does it matter if you get vaccinated against them more than once? What happens in the body?

If swine flu (or some other flu) stays the same what happens in the body if you get the vaccine for it multiple times over the years?

I doubt it matters at all. Its an inactive (dead) virus - the jab, that is - so all it could do is trigger the production of more antibodies to that flu strain, if you haven't already produced them. Could be unnecessary, but can't imagine how it could do any harm iyswim?

Not a scientist though. You need Musukebba

Thanks!

Yes Elibean has it right .

For example immunocompromised patients need two vaccinations - firstly the monovalent Pandemrix H1N1v followed by this year's seasonal trivalent vaccine (containing same strain of H1N1v) - in order to gain sufficient immunity to it.

Thanks Musukebba. So does this mean you can't have too many antibodies to any one type of flu?

(As a non-scientist I thought of the antibodies not leaving room for anything else, or getting out of hand and causing side-effects...)

Aha, Musu to the rescue, as prescribed

I do love the mental image of an antibody getting out of hand, SD! I don't think you can have too many.

Basically yes; each repeat vaccination would boost the immunity (but only up to a point). You lose some over the course of a year so a re-boost the following season would be beneficial.

If a different strain comes along the following year then the immunity to the previous strain will not necessarily protect, so you effectively have to start again from square one with a different vaccine matched to the circulating strain.

No need to worry about the antibodies causing side-effects.

Thanks for taking the time to explain, that's really helpful :)