Booster injection generally refers to the new crown inactivated vaccine booster injection, which has no special precautions and contraindications compared with the previous two injections, but also has the same contraindicated population, and the vaccine booster injection needs to be strictly observed for possible adverse reactions and adverse events after the vaccine booster injection. During the current New Crown epidemic, booster shots generally refer to New Crown inactivated vaccine booster shots. There are currently three types of new crown vaccines on the market, recombinant subunit vaccine, inactivated vaccine, and adenovirus carrier vaccine. Those who have received two doses of inactivated vaccine and are not less than 18 years of age and have no contraindications to vaccination may receive a booster shot six months after the second dose. Booster shots can be given with adenovirus vaccines or recombinant subunit vaccines. Precautions and contraindications for booster shots vary somewhat between vaccine types or manufacturers’ technical routes. The most common inactivated vaccine, for example, is contraindicated in patients with uncontrolled epilepsy or demyelinating lesions, patients with acute illnesses, and patients with acute exacerbations of chronic diseases. After the booster vaccination, it is necessary to be aware of the possibility of adverse reactions such as pain at the site of vaccination, skin rash and itching. During the new crown epidemic, it is recommended to receive booster shots as early as possible without contraindications to enhance antibody levels and reduce the chance of infection.