Here, one vaccination refers to the first vaccination of the new crown vaccine. The first vaccination of the new crown vaccine usually does not cause fever lasting for one month, which is not related to the new crown vaccine, but can be considered to be caused by wound infection, respiratory tract infection and other reasons. 1. Vaccination reaction: After receiving a shot of the new crown vaccine, the vaccine allows the body’s immune system to recognize the immune response and produce protective antibodies. Some adverse reactions may occur including fever, body weakness and other discomforts. However, they usually resolve on their own in 2-3 days. If serious adverse reactions occur, they will be accompanied by allergies, shock and other symptoms. 2. Wound infection: When a needle wound is left in the skin after vaccination with the new crown vaccine, the wound is infected due to exposure to water before the needle wound heals without proper protection, and then a persistent fever occurs. 3. Respiratory tract infection: After receiving the vaccine, the body may be infected by viruses or bacteria that invade the respiratory tract, resulting in recurrent and persistent fever. Fever lasting for more than a month after vaccination is an abnormal situation, and it is recommended to go to a regular hospital to investigate the cause and target treatment.