Is there a third dose for the COVID-19 vaccine?

Generally, the COVID-19 vaccine includes a third dose. The third dose is mostly a booster shot, although in some vaccination schedules it serves as part of the primary immunization series, and receiving it enhances immune protection. Detailed analysis is as follows:

For inactivated vaccines and similar types, after completing the two-dose primary immunization, antibody levels in the body gradually decline over time. Administering a third booster dose at this stage can rapidly reactivate the immune system, increase antibody levels, and strengthen resistance against variant strains. For certain vaccines such as recombinant protein vaccines, the primary immunization schedule itself consists of three doses, and completing all three according to the recommended schedule is necessary to establish complete immune protection.

The third dose should be administered following established guidelines. Booster shots are typically given 6 months after completion of the primary immunization series and may use either the same type of vaccine as the primary doses or an approved heterologous (sequential) vaccination regimen. The third dose of primary immunization must be administered strictly according to the intervals specified in the vaccine’s instructions, and should not be given earlier or later without medical guidance.

Prior to vaccination, individuals should confirm their health status and truthfully inform the healthcare provider about any previous medical history and medication use. After vaccination, remain on-site for 30 minutes of observation, keep the injection site clean and dry, and avoid strenuous exercise.