Sequential booster immunization with vaccines in COVID-19, Henan Province (immunization program in COVID-19, Henan Province)

For those who have not been vaccinated with COVID-19 booster vaccine, there will be a new way to play booster vaccine in the future: you can choose homologous vaccination or heterologous vaccination, that is, sequential booster immunization.

According to the national plan and the requirements of the vaccine group of the provincial epidemic prevention and control headquarters, Henan will carry out sequential immunization on the basis of homologous reinforcement to ensure that the target vaccination targets should be "connected" and establish a group immune barrier in the province.

What is sequential immunization? Who needs to fight? Let's look at the expert interpretation.

What is sequential immunization?

According to experts in disease control, sequential immunization is heterologous immunization, which refers to COVID-19 vaccine with different technical routes when strengthening immunization. For example, the inactivated vaccine was inoculated before. If the inactivated vaccine is selected for booster immunization, it is homologous booster immunization, while if the COVID-19 vaccine is selected for non-inactivated process, it is called sequential booster immunization.

At present, there are three kinds of COVID-19 vaccines in China: inactivated vaccine, adenovirus vector vaccine and recombinant protein vaccine.

Inactivated vaccine is to produce live virus first, and then inactivate the virus by physical or chemical methods to make it vaccine immunity; Adenovirus vector vaccine is to insert the most effective virus antigen gene into adenovirus genome, infect human cells through adenovirus, introduce genes into human cells, and human cells express antigens to stimulate human immune response. Recombinant protein vaccine is the most effective antigen component expressed in vitro through genetic engineering, and cells are often used in biological products. This cell produces this protein through a way similar to industrial fermentation, that is, a bioreactor, and finally it is made into a vaccine.

Why sequential immunization?

Previously, China has been implementing the vaccination strategy of homologous booster immunization, that is, COVID-19 vaccine with the same technical route should be selected for booster vaccination. Now, sequential immunization can be strengthened again. Why?

Shao, a member of the vaccine research and development expert group of the State Council Joint Prevention and Control Mechanism, said that according to the previous experience of infectious disease prevention and control, a single vaccine can deal with conventional viruses, but for cunning viruses that are good at mutation, different vaccines can be used for "joint operations".

"Sequential immunization has two advantages," Shao explained. First, different vaccines can complement each other. Second, for some people, side effects can be reduced. Because different people have different constitutions, some people may have more side effects on a certain vaccine, and the occurrence of side effects can be reduced through vaccine transformation.

Omicron has become the mainstream virus in the world. Wu Liangyou, deputy director of the Municipal Bureau of Disease Control and Prevention of the National Health and Health Commission, said that at present, Omicron mutant has become the dominant strain of imported and local epidemics in China, with stronger transmission power and faster transmission speed, and the risk of imported and local epidemics in China has greatly increased.

To cope with the variation in COVID-19, the World Health Organization supports flexible homologous and heterologous vaccination programs. Wang Huaqing, chief expert of immunization program of China CDC, said that according to research evidence, some countries in America, Europe and Southeast Asia have started to implement sequential immunization.

"The research data shows that both homologous immunization and sequential immunization can further improve the immune effect. It is hoped that people who meet the vaccination conditions can take the initiative to vaccinate and vaccinate as soon as possible." Wu Liangyou said.

Who can choose sequential immunization?

Wang Huaqing, chief expert of immunization program of China CDC, said that there are three conditions for this sequential immunization.

1./kloc-people over 0/8 years old;

Second, complete the vaccination of two doses of inactivated vaccine according to the procedure. The vaccine is one of the three inactivated vaccines in COVID-19, namely Sinopharm Zhongsheng Beijing Company, Beijing Kexing Company and Sinopharm Zhongsheng Wuhan Company.

Third, the immunization was not strengthened, that is, the third injection was not given.

The optional vaccines for this sequential booster immunization in Henan are the recombinant protein vaccine of Anhui Zhifeilong Kyle Co., Ltd. or the adenovirus vector vaccine of Tianjin Kangxinuo Company, and the sequential booster immunization of 1 dose is implemented.

"This group of people can choose sequential immunization, or they can choose the original technical route vaccine for homologous booster immunization." Wang Heng, chief of the immunization planning department of the Center for Disease Control and Prevention in Erqi District, Zhengzhou City, said that at present, 23 outpatient clinics in this district have been trained, and sequential immunization can be carried out tomorrow.

It is also known that at present, Jiaozuo City has taken the lead in initiating sequential immunization.

How is it that someone has a fever after vaccination?

At present, the situation of epidemic prevention and control at home and abroad is severe and complicated. The Henan Provincial Center for Disease Control and Prevention reminds everyone to continue to maintain a high degree of protection awareness, adhere to scientific wearing of masks, frequent hand washing, frequent ventilation, avoid gathering, maintain a safe social distance, and develop good hygiene habits. Don't go to high-risk areas if it is not necessary. At the same time, COVID-19 vaccine should be vaccinated as soon as possible, and intensified vaccine should be actively vaccinated after 6 months to avoid the risk of infection.

Some people wonder why some people have adverse reactions such as fever after vaccination.

"After vaccination, as a biological product, it may cause fever, rash and induration. This is the characteristic of biological products, and it also shows that the immune system responds to vaccines. " Wang Heng said that this is a normal phenomenon. Generally, it will relieve itself in a day or two. Don't panic. After vaccination, you should stay in hospital for observation for 30 minutes. When there is any adverse reaction suspected to be related to vaccination, if it lasts for a long time and the symptoms are serious, first, you should report it to the vaccination unit, and second, you should seek medical advice in time.