The redness, swelling and hardness of the vaccine eye may be caused by the body’s response, or the unabsorption of the drug, or it may be the cause of secondary infection. 1. Organism response: Mostly considered because after vaccination, some components in the vaccine cause stimulation to the local tissues, which leads to the body to produce a defense response, which is a common manifestation after vaccination. 2. Drugs are not absorbed: if the vaccination process, because of improper injection, resulting in drug extravasation or tissue does not absorb the drug, to a certain extent, also prone to needle eye redness, swelling and hard lumps of its situation. 3. secondary infection: in addition, if you do not pay attention to local skin care after vaccination, keep dry and clean, premature touch of water, it is easy to be infected by pathogenic microorganisms, resulting in vaccine eye redness, swelling and hard lumps. Under normal circumstances, the redness and swelling of the vaccine eye can subside in 1~2 days, if the symptoms are obvious, and the redness and swelling do not subside for a long time, you need to go to the hospital in time.