Also, is it true that flu vaccine can cause brain swelling ?

Rare but it can: Reported moderate reactions to influenza vaccine include fever, local reactions (pain, redness, swelling at the site of the injection), headache, fatigue, sore throat, nasal congestion, cough, joint and muscle pain, and nausea. Reported serious complications include brain inflammation, convulsions, bell’s palsy, limb paralysis, neuropathy, shock, wheezing/asthma and other breathing problems. Guil.