At the press conference of the State Council's Joint Prevention and Control Mechanism on February 19, it was announced that China had begun deploying sequential booster immunizations.

  Sequential booster immunizations are commonly known as "mixed fights".

Why Sequential Vaccination?

How to perform sequential vaccination?

These issues will be clarified at one time at the press conference!

  【1】What is sequential booster immunization?

  [Concurrent] Wang Huaqing, Chief Expert of Immunization Program of China CDC

  Sequential immunization has also been applied to this immunization strategy in the past. It is that vaccines of different technical routes are vaccinated according to a certain interval of time and the number of doses of vaccination (mixed vaccination). (Yes) In order to further improve the protective effect, it also To consider its safety, an immunization strategy adopted.

  【2】Why do we need sequential booster immunization?

  [Concurrent] Shao Yiming, member of the expert group for vaccine research and development of the scientific research team of the joint prevention and control mechanism of the State Council

  Generally, for conventional viruses or diseases that are easy to deal with, it is enough to use a single vaccine, but for some viruses that are highly variable and difficult to deal with, sequential immunization is often used.

There are two main purposes: one is that different vaccines can complement each other's advantages, and the other is that individual physiques are different, which may have more side effects on a certain type of vaccine, so that we can change a vaccine to avoid side effects.

  【3】Is sequential booster immunization safe?

  [Concurrent] Shao Yiming, member of the expert group for vaccine research and development of the scientific research team of the joint prevention and control mechanism of the State Council

  The WHO and some European and American countries have carried out a large number of sequential vaccination trials, including adenovirus vector vaccines, protein vaccines, and mRNA vaccines added to inactivated vaccines in our country, and some are reversed. On the basis of mRNA vaccine, other vaccines are used, and the results of these studies are all safe.

  【IV】Which vaccines can be used for sequential immunization?

  [Concurrent] Wu Liangyou, deputy director of the National Health Commission's Bureau of Disease Control and Prevention

  After the implementation of the sequential booster immunization strategy, the target population who have completed the whole process of inoculating the three inactivated vaccines can also choose the recombinant protein vaccine of Zhifeilong Kema or the adenovirus vector vaccine of CanSino for sequential booster immunization.

For the target population, one of homologous booster immunization and sequential booster immunization can be selected.

  【V】What are the precautions for sequential immunization?

  [Concurrent] Wang Huaqing, Chief Expert of Immunization Program of China CDC

  Regarding the objects of this sequence of immunization, the first one is the people over 18 years old, and the second one is that he has to complete 2 doses of inactivated vaccines, and these 2 doses of inactivated vaccines are from Sinopharm Zhongsheng Beijing Company, Vaccines from Beijing Kexing Company and Sinopharm Zhongsheng Wuhan Company.

The third is that the vaccination interval should be 6 months (above).

The fourth is that the booster immunization has not been carried out, that is, the third injection has not been played.

  [6] What is the international view on sequential immunization?

  [Concurrent] Wang Huaqing, Chief Expert of Immunization Program of China CDC

  From the perspective of the World Health Organization, it supports flexible vaccination, whether it is homologous vaccination or heterologous vaccination, or sequential immunization, and he still supports such a vaccination plan.

He has a suggestion that when we consider heterologous vaccination and sequential vaccination, its immunogenicity or effectiveness is not lower than or higher than the results of homologous vaccination.

In addition, it is also recommended to use a vaccine with a different technical route from the first dose for heterologous vaccination.

  Reporter Wen Mengxin reports from Beijing

Responsible editor: [Song Fangcan]

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