2 doses of inactivated + 1 dose of adenovirus The NEW CROWN vaccine sequentially strengthens the start

On February 19, the joint prevention and control mechanism of the State Council held a press conference to announce the new plan for the sequential strengthening of immunization against COVID-19 vaccines. The announcement of this news clarifies the adjustment of the mainland's strategy of opening sequential vaccination of the new crown vaccine, which is an accurate force on the current epidemic prevention and control situation and is of vital significance to the mainland's "external prevention of imports, internal prevention of rebound" blockade battle.

(Source: CCTV News)

Building a Solid Immune Barrier It is imperative to start sequential strengthening

The new crown virus is constantly mutating, and the new coronavirus such as Omi Kerong has spread to many countries around the world. According to the latest real-time statistics from WHO, as of February 18, Beijing time, the cumulative number of confirmed covid-19 cases worldwide exceeded 420 million, and the cumulative number of deaths was 5.88 million. It is understood that the new coronavirus mutation strain has evolved multiple lineages, and the epidemic situation is very serious.

In order to further consolidate the immune barrier of the whole population and enhance the protective power of vaccines, the mainland launched the intensification of COVID-19 vaccination in October last year. According to data reported by the National Health Commission, as of February 15, the total number of domestic vaccinations was 1.267 billion, of which 502 million people had completed enhanced immunization.

At the time of vigorously promoting the strengthening of the needle in China, the sequential immunization research and pilot work supported by the expert group of the vaccine research and development special class of the National Health Commission have also achieved results. Studies have shown that after COVID-19 vaccination, the level of antibodies in the body of the vaccinated person decreases over time. Sequential vaccination can increase the immune response through complementarity between different mechanisms, bring more comprehensive and powerful protection, and play the role of 1+1>2.

After the prologue was approved, the reinforcement needle had two ways of playing

Up to now, 7 NEW CROWN vaccines in the mainland have been approved for conditional marketing or emergency use. Including 5 inactivated vaccines, 1 adenovirus vector vaccine, and 1 recombinant protein vaccine.

At present, most people in China are vaccinated with two doses of inactivated vaccine. Since the launch of the intensification of covid-19 vaccination, the public's choice can only be homologous vaccination, that is, to continue to receive inactivated vaccines. So after the sequential reinforcement was approved, how many ways to play the reinforcement needle now? Which effect is better?

There are two options, one is the same technical route of enhanced inoculation, which we call homologous enhancement. The other refers to the alternating vaccination of vaccines of different technical routes, which we call sequential reinforcement. To put it simply, the two-shot inactivated vaccine that was previously given, the booster injection is still inactivated, belongs to the homologous strengthening; if the two-shot inactivated vaccine that was previously given, the reinforced injection of the adenovirus vector new crown vaccine or the recombinant protein vaccine, belongs to the sequential strengthening.

Zheng Zhongwei, head of the vaccine research and development working group of the joint prevention and control mechanism of the State Council, said in an interview: "Through the strengthening of sequential immunity, the level of antibodies will be more improved."

Adenovirus vector COVID-19 vaccine sequence enhancement data is eye-catching

Data indicate that the use of adenovirus vector COVID-19 vaccines to inactivate COVID-19 vaccines is sequentially strengthened, has good safety, and can obtain higher immune efficacy. Previously, an animal experiment study of the Central Inspection Institute showed that after receiving two doses of inactivated new crown vaccine, different vaccines were used to strengthen immunity, and the adenovirus vector vaccine had the best effect, and the strengthening effect of inactivated or recombinant protein vaccines was significantly lower than the former.

From the perspective of safety, the results of the global multi-center Phase III clinical trial of the recombinant novel coronavirus vaccine (type 5 adenovirus vector) developed by CanSino Biologics were announced in The Lancet. The data show that 1 dose of adenovirus vector COVID-19 vaccine in healthy people aged 18 years and older is safe and effective. After 14 days, the critical illness protection rate was 96.0%, the overall protection rate was 63.7%, meeting the standard of protection rate recommended by the World Health Organization for the new crown vaccine, and no serious adverse reactions related to the vaccine occurred.

In terms of effectiveness, when two doses of inactivated vaccine are given, another dose of adenovirus vector COVID-19 vaccine is given as a boost. The study data showed that the antibody level exceeded the inactivated vaccine homologous enhancement immunity by 5 times, and the recombinant protein vaccine sequential enhancement by 7 times. In addition, for the Omiljung variant, the research data showed that the neutralizing antibody level of the adenovirus vector new crown vaccine sequential enhancement was 3 times that of the recombinant protein vaccine sequential strengthening, the inactivated vaccine homologous enhancement was 6 times, and the adenovirus vector vaccine enhancement effect was excellent.

The above studies show that the sequential strengthening of the new crown vaccine using adenovirus vector has good safety and immunogenicity. For existing COVID-19 mutant strains, sequential vaccination against adenovirus vectors is effective, and its overall protection rate and critical illness protection rate are maintained at a high level.

Sequential vaccination is widely used in many countries safety and immunogenicity have been verified

It is reported that the World Health Organization (WHO) has issued interim guidelines for the sequential strengthening of the new crown vaccine based on existing research data. The guidelines suggest that, based on available evidence, sequential vaccination with vector vaccines or mRNA vaccines show enhanced immunogenicity and neutralizing antibody levels are superior to inactivated vaccine homologous booster immunity compared with homologous vaccination procedures using inactivated vaccines alone.

According to the latest public information, many countries and regions in the world have approved the use of "sequential" immunization as a booster vaccination strategy for the new crown vaccine. In particular, the use of adenovirus vector COVID-19 vaccines can effectively strengthen protection for other vaccines and reduce the incidence of severe diseases.

The U.S. Food and Drug Administration (FDA) has approved a mixed vaccination regimen that uses different types of vaccines as enhancers.

The Argentine Ministry of Health recommends on its website that CanSino's adenovirus COVID-19 vaccine Kwesa can be used as a booster vaccine for people who have received 2 doses of inactivated vaccine.

Brazil's Ministry of Health said that the Johnson & Johnson adenovirus vector COVID-19 vaccine or the Oxford AstraZeneca adenovirus vector COVID-19 vaccine could be used as boosters.

People in Chile who received two doses of inactivated vaccine were given adenovirus vector vaccine as boosters of immunity from August last year.

In the future, there may be better options for injecting with the new crown vaccine. CanSino Bio's world's first inhaled COVID-19 vaccine, which only needs to be inhaled like milk tea to complete the vaccination process. It can not only stimulate humoral and cellular immunity, but also efficiently induce mucosal immunity to achieve triple comprehensive protection, with good safety and immunogenicity, and can establish an immune barrier for more people.