2. COVID-19 vaccine is an inactivated vaccine with high safety, but for people with special physique, there may still be some adverse reactions after vaccination. But if two injections are given at the same time, the adverse reaction will be more serious, which is not conducive to finding allergens.

3. Therefore, it is suggested that the two injections of COVID-19 vaccine should be carried out separately, and the interval between the two injections should be at least 14 days to reduce the occurrence of adverse reactions. In addition, it should be noted that the inoculation time of the second dose of COVID-19 vaccine can not be adjusted at will, because adjusting the immunization program of COVID-19 vaccine at will may affect its safety, immune response effect and immune persistence.