Symptoms of fever after the New Crown vaccine may be due to an adverse reaction caused by the New Crown vaccine. Some patients may experience a transient fever after receiving the New Crown vaccine because of the effects of the ingredients in it. The symptoms are generally mild, often low and of short duration. In this case, it is only necessary to monitor the change of the patient’s body temperature, pay attention to the hydration and nutrition, and ensure sufficient rest, and generally, the patient will recover spontaneously in 2-3 days. However, if the fever is more severe and exceeds 38.5°C, symptomatic treatment such as acetaminophen or ibuprofen can be given. If there is a high fever or fever for a longer period of time, there are usually pathological factors, and patients are advised to seek medical attention at hospitals with fever clinics and report to the relevant disease control departments in a timely manner. Patients need to undergo relevant examinations to clarify the cause of the disease and carry out treatment under the guidance of a doctor to avoid delaying the condition. In addition to fever, there may be local reactions such as redness, swelling, nodules and pain at the injection site or systemic reactions such as headache, nausea, muscle pain, weakness and fatigue after the injection of the new crown vaccine, but the symptoms are usually mild and usually do not require treatment and will resolve on their own after a period of time. Usually, it is necessary to stay at the vaccination site for 30 minutes after vaccination to avoid allergic reactions, such as redness and rash on the skin or even coma and shock. In addition, after the vaccination, pay attention to the dryness and cleanliness of the injection site, and personal protection is still needed after the injection.