There are three kinds of vaccines. The first two doses of inactivated vaccine are basic immunity, and the purpose of the third dose is to strengthen immunity. The interval between the first two doses is suggested to be completed within 3 to 8 weeks, and the third dose should be inoculated after 6 months. The basic immunity of adenovirus vector vaccine is one dose, and the purpose of the second dose is to strengthen immunity. The interval between the two doses of vaccine is at least 6 months, and it is recommended that the recipients use the same variety of vaccine for booster immunization. There are 3 doses of recombinant subunit vaccine in the whole process of basic immunization, and there is no booster at present. The interval between two adjacent doses is at least 4 weeks. The second dose should be injected within 8 weeks after 1 dose, and the third dose should be injected within 6 months after 1 dose.
It is worth noting that it is recommended to use the vaccinated vaccine for booster immunization. In principle, recipients who use the same inactivated COVID-19 vaccine to complete two doses of injection will also use this inactivated vaccine for enhanced immunization; In principle, recipients who have completed two doses of different inactivated vaccines should give priority to the second dose of inactivated vaccine for enhanced immunization. If the second dose of the same vaccine can no longer be supplied, they can use the same vaccine as 1 dose inactivated vaccine for booster immunization. The recipients who use the adenovirus vector vaccine for injection shall use the original vaccine to strengthen their immunity.