M.H.
The facts are that the immune system is capable of fighting off the flu. He seems to be very protected by you in staying home and being breast fed. The flu vaccine is full of chemicals (preservatives) that break down the immune system. Even IF it prevents the flu, it has started a "breakdown" process that is hard to reverse.
The CDC will also tell you (online) that the flu vaccine is made from the previous year's strain and it might not be effective.
My two cents!
M.