The inactivated New Crown vaccine is not harmful if only one shot is given, but if only one shot is given for a vaccine that requires 2 to 3 shots, the immune effect will be relatively poor, and the resistance to the New Crown virus will be insufficient, increasing the likelihood of infection. At present, China’s commonly used new crown vaccine type for inactivated vaccine, generally need to be vaccinated with two shots, there are some can be vaccinated with one shot and three shots. If you need to be vaccinated with two or three shots of inactivated new crown vaccine, only the first shot, the immune effect is relatively poor, can not play a good protective effect, it is recommended that only a shot of the population in the prescribed time, as soon as possible to complete the next dose of vaccination work. Generally the interval between the first and second shots should be at least three weeks, and the latest is generally not more than eight weeks, and the interval between the third and second shots should be at least four weeks, but the interval with the first shot should not exceed six months. The inactivated NeoCollins vaccine is important for preventing infection with NeoCollins pneumonia, and it is recommended to be fully immunized in a timely manner. [Note: In this article, the terms “new coronavirus pneumonia” and “new coronavirus pneumonia” were renamed to “new coronavirus infection” on December 26, 2022, as announced by the National Health Commission.