The first dose is Concinol and the booster dose also requires Concinol vaccine and is not applicable to sequential vaccination. If the first dose of NeoCrown vaccine was given with Coxinol NeoCrown vaccine, a booster dose of Coxinol vaccine is also required. The Concinol vaccine is an adenovirus-vectored vaccine, which is produced differently from the inactivated vaccine and cannot be mixed at this time. The so-called sequential vaccination mainly refers to the fact that the first two doses of Neo-Conjugate vaccine are inactivated vaccines, and the third booster dose can be given with other types of vaccines, such as adenovirus-vectored vaccines, recombinant protein vaccines, and so on. The principle of sequential vaccination is not applicable to the first vaccination with adenovirus vector vaccine. It is recommended to consult the staff at the vaccination site before vaccination.