What does sequential vaccination mean?

In general, heterologous vaccination (or sequential vaccination) refers to using vaccines based on different technological platforms for booster doses after completing the primary immunization series. A detailed explanation is as follows:

The core idea of this vaccination strategy is to leverage the distinct immunological characteristics of vaccines developed from different technologies, thereby stimulating a broader and stronger immune response in the body and enhancing overall protection. For example, if inactivated vaccines are used for the primary series, using adenovirus vector vaccines or mRNA vaccines as booster doses constitutes heterologous vaccination. Because vaccines based on different technological platforms have varying mechanisms of action, their combined use can complement each other's strengths, boosting antibody levels and prolonging immune durability. Heterologous vaccination must strictly follow official vaccination guidelines, meeting specified dosing intervals and target population criteria, and is not suitable for all vaccines or individuals.

When receiving vaccinations, individuals should first understand their primary immunization history and follow the instructions provided by vaccination sites to ensure proper and effective immunization.