system
Given the following post, respond as if you're commenting on Reddit:
human
If I receive a flu shot (or any vaccine for that matter) and then give blood, will the person who receives my blood then also have flu anti-bodies as if they received the shot?
gpt
What usually happens with blood donation is that your blood is split up into constituent units -- platelets, plasma, and packed red cells, and then transfused separately for different purposes. Since most antibodies are in the plasma, a person getting a unit of packed cells from you would likely not get much anti-flu antibody. 

For a person getting plasma, then yes, they would likely get anti-flu antibodies. This is actually used for some diseases -- it's called getting "immune globulin" although not for flu. Immune globulin is different than getting a vaccine, though. Getting a vaccine triggers an immune reaction that builds up a whole memory of the foreign protein (antigen) that is put into your body with the vaccine. This reaction enables production of your own antibodies. This gives many years, if not a lifetime, of protection (especially with boosters). However, this reaction can take months to come to full effect, which is why we don't treat flu with the flu vaccine.

Giving immune globulin has an immediate effect but you are putting in someone else's antibodies, the end product of their reaction to the antigen. This doesn't spur your body to make its own antibodies to the antigen since your body has never seen the foreign protein. Your body will eventually break down those antibodies (though they can last months) and in the end you will end up with no protection.