Inactivated vaccines are basically free from infection because there are no viruses of toxic force, and in this respect they are safer than attenuated vaccines. Inactivated vaccines are mainly made after one obtains the pathogenic microorganism corresponding to the vaccine, and then the pathogenic microorganism is completely inactivated by certain treatment to obtain a killed pathogenic microorganism, and thus a live vaccine is made. It is actually a kind of corpse of the killed pathogenic microorganism, or a part of it that is resistant to the drug. After use, it will neither infect a person with a disease nor stimulate the body to produce the corresponding antibodies to defend against the invasion of the microorganism, such as the pertussis vaccine and the influenza vaccine that are now used are inactivated vaccines. They are safer than attenuated vaccines, but there are a few people who may be allergic to the vaccine and may have certain adverse reactions.