There are various types of vaccines, and the number of vaccinations may vary for different diseases. And the number of vaccinations may also vary for vaccines that prevent the same disease, depending on the type of vaccine. Vaccines that are commonly given in one shot include BCG vaccine and adenovirus vector vaccine for New Coronary Pneumonia, which provide defense after one shot. There are also vaccines that require three doses, such as hepatitis B vaccine, cervical cancer vaccine, and recombinant protein vaccine for New Crown pneumonia. Of course, there are also vaccines that require four doses, such as the diphtheria vaccine. Some vaccines are more efficient, as one dose can stimulate the immune system to produce memory cells and provide an immune effect. Some vaccines can only produce a small amount of antibodies after the first dose, and a second booster dose is required to boost the immune memory response. Generally, the full dose of vaccination is completed to achieve better protection. Therefore, the number of vaccine doses required depends on the type and type of vaccine, and the number of vaccine doses required cannot be used to determine the strength of the vaccine’s effect. The number of vaccine injections is based on repeated clinical trials, so you should follow your doctor’s instructions. Although there are different doses of the new crown vaccine, the immunization effect is good, so you should respond to the national call for active vaccination.