Neocoronavirus vaccine does not cause obesity and weight gain is mainly due to self-inflicted factors. Neocoronavirus vaccines are mainly inactivated Neocoronavirus, recombinant subunits, adenovirus vectors and other types, which do not cause weight gain. The vaccine mainly works on the immune system, stimulating the production of antibodies to protect the immune system. Therefore, vaccines do not cause weight gain and there is no direct link between the two. If weight gain occurs, it is mainly considered to be caused by self-factors, such as increased food intake and lack of exercise. Such as increased food intake, lack of exercise, etc., weight gain is obvious. In addition, it may also be caused by endocrine abnormalities, metabolic decline and other factors, and there is no obvious connection with the vaccine. Therefore, it is recommended to strengthen exercise, as well as regular medical checkups to detect the disease as early as possible.