COVID-19's continuous intensive vaccination has finally begun. In addition to COVID-19 inactivated vaccine, you can also choose to inoculate 1 dose of recombinant protein for the third injection.

The long-awaited sequential booster immunization of COVID-19 vaccine has finally been implemented. In addition to inactivated COVID-19 vaccine, you can also choose to inoculate 1 dose of recombinant protein vaccine or adenovirus vector vaccine for the third injection.

On February 18, news was sent from Wuhan, Hubei, Shangrao, Jiangxi and Jiaozuo, Henan. For people over the age of 18 who have been vaccinated with two doses of inactivated COVID-19 vaccine for six months and have not been vaccinated with the third dose of inactivated vaccine, sequential booster immunization can be implemented, that is, non-inactivated vaccine is used for booster immunization, and recombinant protein vaccine or adenovirus vector vaccine is selected.

Previous studies have shown that after inoculation with two doses of inactivated vaccine, sequential booster with adenovirus vector vaccine has good safety, and the antibody level is better than homologous booster. At the same time, some studies show that on the basis of two kinds of inactivated vaccines, the human body's neutralization ability to Omicron strains is better than homologous enhancement by using recombinant protein vaccines in turn.

Sequential immunization was carried out in Wuhan, Shangrao and Jiaozuo.

At present, "homologous booster immunization" is widely practiced in China, that is, booster immunization adopts the same technical route as basic immunization for vaccination. For example, 2 doses of inactivated vaccine for basic immunization +65438+ 0 dose of inactivated vaccine for strengthening; Or adenovirus vector vaccine 1 dose sub-basic immunization+adenovirus vector vaccine 1 dose booster immunization.

On February 18, Wuhan City, Hubei Province, Shangrao City, Jiangxi Province, and Jiaozuo City, Henan Province announced a new plan for strengthening immunization, namely "sequential strengthening immunization", which refers to strengthening immunization with vaccines with different technical routes from basic immunization.

According to the official account of "Wuhan CDC" on February 8/kloc-0, at present, two doses of inactivated vaccine (Vero cells) and 1 dose of recombinant protein vaccine (CHO cells) can be implemented in China to strengthen immunization; Or inactivated vaccine (Vero cells) 2 doses of sub-basic immunization+adenovirus vector vaccine 1 dose of booster immunization.

Sequential immunization program. Source: "Wuhan CDC" WeChat WeChat official account

As for the target population, it is reported that at this stage, the inactivated COVID-19 vaccines of Sinopharm Zhongsheng Beijing Company, Beijing Kexing Company and Sinopharm Zhongsheng Wuhan Company can be inoculated in turn in people aged 18 years and above who have not completed homologous booster immunization for six months. The work strategy will be adjusted in time according to the national deployment.

On February 18, WeChat of Shangrao CDC released the professional answer of COVID-19 vaccine "sequential immunization", and WeChat of Jiaozuo Daily also released a message that our city started the sequential immunization of COVID-19 vaccine, and the sequential immunization projects and target population in Shangrao and Jiaozuo were the same as those in Wuhan.

According to the above three sources, sequential booster immunization is free at this stage, and homologous booster immunization is still available.

Compared with homologous enhancement, what is the effect of sequential enhancement?

According to "Shangrao CDC" WeChat February 18 news, the current related research results show that after inoculation of two doses of inactivated vaccine, sequential reinforcement with Ad5 adenovirus vector vaccine has good safety, and the antibody level is superior to homologous reinforcement, which can effectively neutralize mutant strains. After sequential inoculation, the cellular immune response of human body is significantly stimulated, which plays an important role in activating the secondary response of cells in vivo and effectively removing cells infected by the virus.

As early as September, 20021year, Kangxinuo Bio released a message through official WeChat WeChat official account, saying that the clinical trial results showed that after being strengthened with Kangxinuo Bio-adenovirus vector COVID-19 vaccine, it showed good safety and no serious adverse reactions related to the vaccine were found. It also shows that the growth level of neutralizing antibody produced after sequential enhancement is obviously better than that of homologous enhancement.

According to the news, according to the research data, the researchers inoculated the volunteers with two doses of inactivated vaccine, and then injected an adenovirus vector COVID-19 vaccine as a reinforcement. After 14 days, the neutralizing antibody GMTs was197.4 (167.7,232.4), and the antibody level increased about 78 times. If the third dose is strengthened with inactivated vaccine, the antibody level is 33.6 (28.3, 39.8), which is about 5.2 times higher than/kloc-0.

So, what is the effect of using recombinant protein vaccine to enhance immunity?

On February 23rd, 20021/kloc-0, the National Center for Infectious Diseases and the Infectious Diseases Department of Huashan Hospital affiliated to Fudan University published related articles on their micro-signal "Huashan infection". According to the article, the team of Huashan Infectious Diseases Department recently evaluated the subjects vaccinated with two doses of inactivated vaccine for the first time in the world, and the third dose of homologous vaccine enhanced the neutralization ability of the subjects' serum to Omicron.

The results showed that the neutralizing antibody titers of antigen strain, Delta strain and Omicron strain in serum increased to 285.6, 250.8 and 48.73 respectively after the third booster injection of 14. If the recombinant subunit protein was injected for 14 days for the third time, the titer of neutralizing antibody against the original strain, δ strain and Omicron strain in serum increased to 1436, 150 1 and 95.86 respectively.

Studies have confirmed that, on the basis of two doses of inactivated vaccine, the third dose of homologous vaccine and heterologous vaccine enhanced the human body's neutralization ability to Omicron strain by 8.07 times and 65438 05.87 times respectively. At the same time, the titer of neutralizing antibody against the original vaccine strain was also increased by 4.24 times and 2 1.3 1 times respectively.