Animals vaccinated after the immune function has nothing to do with the detrimental to the body's adverse reactions known as immune side effects. Immune side effects are divided into general side effects, severe side effects and side effects. General side effects do not cause physiological dysfunction, no need for treatment, the reaction will continue for 1 ~ 2 d after self-limiting. This is determined by the biological characteristics of the vaccine, such as pigs vaccinated live vaccine, vaccine strains can be in vivo reproduction and reproduction, similar to mild natural infection clinical symptoms. Once the serious reaction of livestock and poultry, to timely symptomatic treatment and rescue, otherwise it will cause serious consequences.