Attentions should be paid to inactivated vaccine: firstly, it should be carried out under the condition of good poultry body; Secondly, inactivated vaccines generally need to be immunized for more than 2 times, and intramuscular inoculation is used; Thirdly, when young poultry are immunized for the first time, the peak period of maternal antibody should be avoided as far as possible. In addition, the immunization of waterfowl such as ducks may have some side effects.