FAQs on China's COVID sequential booster immunization

5. Has the sequential immunization strategy been adopted in other countries?

A number of countries in the Americas, Europe and Southeast Asia have already begun using different vaccines from those originally given for their booster shot programs.

The World Health Organization said it supports a flexible approach to boosting with a same or different dose.

6. What is the safety and efficacy of the sequential immunization strategy?

The approach has proved to be safe and effective based on domestic and foreign studies.

No additional side effects were found to be linked to a sequential booster.

6. Do I need to have both homologous and sequential booster vaccinations?

Research has shown either boosting with a dose that is the same as the initial inoculation or with a dose developed with a different technology is effective at further improving immunity against COVID-19. The eligible group only needs to choose one of them.