At present, there are two main types of clinical booster shots for the third injection, including sequential vaccination and homologous vaccination, both of which can play a certain preventive effect on the new coronavirus, and generally there is no argument about which one is better. Sequential vaccination also belongs to a kind of booster shot, generally using a different technical route of vaccine with the basic immunization for booster immunization. For example, if two doses of inactivated New Crown vaccine have been given, and a subsequent booster is given with any other non-inactivated New Crown vaccine, this would be considered sequential vaccination. It is required after 2 doses of vaccine and at an interval of 6 months before the vaccination can be given. After the implementation of the sequential booster vaccination strategy, the target population who have completed the full course of inactivated vaccination can also choose the recombinant protein vaccine of Jifironkoma or the adenovirus vector vaccine of Concinol for sequential booster vaccination. Therefore, either sequential vaccination or homologous vaccination can achieve better immunization results, and those who meet the vaccination requirements only need to choose one to be vaccinated.