At this time, there is no official indication from China that a fourth dose of the New Crown vaccine is required. The New Crown vaccine currently requires two or three doses. The timing and intervals of vaccination are strictly according to the vaccine instructions. Protective antibodies produced after vaccination will remain in the body for a certain period of time. If necessary, a fourth dose of vaccine may be given in the future to achieve effective immunization. At least two or three doses of the New Crown vaccine are required for the body to produce effective antibodies for good protection and prevention. After the New Crown vaccine is administered, rest and observation are required. After 30 minutes, if there is no adverse reaction such as dizziness or fatigue, you can leave the vaccination site. After returning home, you should pay attention to rest, avoid eating spicy food, avoid drinking alcohol, do not stay up late, etc.. If there is any adverse reaction after the injection of New Crown Vaccine, you need to consult a doctor in time.