The principle of prophylaxis is to prevent a specific disease through vaccination. The main principle of vaccination is that a specific bacterium or virus is attenuated or inactivated to produce a vaccine. By inoculating a person, such substances enter the body and act as antigens that stimulate the immune system to form corresponding antibodies. When exposed to a specific virus, the antibodies in the vaccinated person’s body can quickly develop resistance to the virus, blocking the virus from entering the body and causing infection, which is the main principle and mechanism of its action. Although there are cases in which vaccination still causes infection, such as in the case of the New Crown vaccine, the role of vaccines in disease prevention is extremely important and has greatly prevented the spread of a number of diseases in terms of overall infection rates.