The CHO vaccine is a genetically recombinant vaccine. The CHO vaccine is not recommended probably because the antigenic component extracted from this vaccine is limited compared to the inactivated vaccine, and the chance of failure of the vaccination will be increased if the extracted antigenic component cannot cover the new mutated virus after the mutation of the virus. This vaccine is a vaccine made by extracting the most effective antigenic component and expressing the antigenic protein in cells in vitro through genetic engineering. The advantages of this vaccine are high safety and lower incidence of adverse reactions than other vaccines, but the antigenic component is less than that of inactivated vaccines, so the ability to resist virus mutation is weak and the vaccine will fail due to genetic mutation of the virus expressing the vaccine antigenic component. Phase III clinical trials of the CHO vaccine have shown a protection efficacy of about 92.93% against the currently popular Alpha variant and a higher protection efficacy against the Delta variant than other vaccines, indicating that the CHO vaccine is still vaccination is still available. However, since the epidemic abroad has never been controlled and there is a high chance of virus mutation, inactivated vaccine is recommended if there are plans to go abroad, and CHO vaccine is not recommended. The CHO vaccine requires three doses at an interval of no less than 28 days, and if time does not permit, other vaccines are available. If the patient has contraindications to vaccination, vaccines other than CHO vaccine are also not suitable, but in the case of rabies vaccine, tetanus antitoxin, etc., because the consequences of non-vaccination are much more serious than vaccination, contraindications can be disregarded.