Expert interpretation of adenovirus vector vaccine: single-dose vaccination accelerates the construction of immune barrier

(Fighting New Coronary Pneumonia) Expert Interpretation of Adenovirus Vector Vaccine: Single-dose vaccination accelerates the construction of immune barrier

　　China News Service, Beijing, March 1 (Reporter Li Chun) At the media communication meeting with experts on the prevention and treatment of new coronary pneumonia and vaccine application held in Beijing the day before, Yu Xuefeng, chairman of Cansino Biotech Co., Ltd., introduced that the recombinant new coronavirus vaccine ( Type 5 adenovirus vector) uses a single-dose vaccination method to allow as many people as possible to be vaccinated and to suppress the pandemic trend as soon as possible.

　　On February 25, the State Drug Administration of China conditionally approved the registration application for the recombinant new coronavirus vaccine (type 5 adenovirus vector) of Cansino Biotech Co., Ltd.

The vaccine was developed by a team led by Chen Wei, an academician of the Chinese Academy of Engineering and a researcher of the Academy of Military Medicine of the Academy of Military Sciences, in cooperation with CanSino Bio, and it is also China's first approved adenovirus vector new crown vaccine.

　　According to public reports, Keweisha uses a single-dose immunization program that can be stored stably at a temperature between 2 and 8 degrees Celsius. The vaccination targets are people aged 18 and above.

On March 16, 2020, the vaccine took the lead in launching Phase I clinical trials in Wuhan, and entered Phase II clinical trials in Wuhan on April 12.

The vaccine was launched in a global multi-center phase III clinical trial in September, and vaccinated more than 40,000 subjects in more than 70 clinical research centers in 5 countries.

　　The communication meeting on the same day also revealed that the vaccine's Phase III clinical trial results showed that a single injection can produce effective protection 14 days after vaccination. The overall protection effect on all symptoms is 68.83%, and the protection effect on severe illness is 95.47%.

In addition to generating high-efficiency humoral immunity, it can also induce cellular immune responses in the body.

　　Yu Xuefeng said that the vaccine uses a single-dose immunization program, with the aim of expanding the coverage of the vaccine, building a herd immune barrier as soon as possible, and stopping the pandemic as soon as possible.

Generally speaking, phase III clinical trials need to observe the protection period of the vaccine for one year, but in the context of the current global pandemic of the new crown epidemic, there is no such ample time. This is why the current vaccine approvals are “conditional”. "of.

　　Looking back on the global new coronavirus vaccine development process for more than a year, this recombinant new coronavirus vaccine (type 5 adenovirus vector) in China entered clinical trials first, but before its marketing registration application was approved, there were already two inactivated new coronavirus vaccines With the conditional approval of the State Food and Drug Administration of China, an inactivated new crown vaccine was approved on February 25 on the same day.

　　Why is it the first to carry out clinical trials in the world but not the first to be approved for marketing?

Yu Xuefeng said that vaccines are conducting global multi-center phase III clinical studies in more than 70 clinical research centers in 5 countries, with strict standards and complicated processes.

This makes the progress of the research and development somewhat "postponed", but ensures that the test results can withstand scrutiny.

　　Long-term stable storage between 2 and 8 degrees Celsius is a major feature of this vaccine.

Yu Xuefeng said that this makes the vaccine easy to transport and store, reduces the burden on the use of primary vaccines, and improves the accessibility of the vaccine.

　　At present, the United Kingdom, South Africa, Brazil, Japan and other countries have reported the detection of mutated new coronaviruses, and they have even become the dominant strains in some places.

Whether the current vaccine can cope with the mutation of the virus is a topic that has always been concerned by all parties.

　　Yu Xuefeng said that for most of the current strains, the protective effect provided by the new crown vaccine is not much different, even if the key points are changed, which affects the effect of the existing vaccine. With the current production technology level of the new crown vaccine, Can be updated quickly.

　　Speaking further about virus mutation, Feng Luzhao, executive vice president of the School of Medicine and Public Health of Peking Union Medical College, pointed out that the key point is whether the mutation occurs at the key point of the virus gene, so as to affect the transmission, pathogenicity, and vaccine effect of the virus. , The sensitivity of the detection reagent has an impact.

　　"General mutations are like'changing clothes' and do not affect my recognition of you. However, if you have undergone a'plastic surgery' and change particularly important characteristics, this important mutation may affect the characteristics of the virus and affect the vaccine. The effect." Feng Luzhao said.

　　Speaking of the future coexistence of the new coronavirus with humans, Feng Luzhao believes that the relevant trends and status are still uncertain. People's understanding of this virus is still deepening, but there are three points that can be confirmed.

　　First of all, unlike SARS, which are mostly severely ill patients, there are a large number of asymptomatic infections of the new coronavirus, which also makes it difficult to eradicate the new coronavirus.

Secondly, if cases are detected early and prevention and control are good, the proportion of severe cases and deaths will become lower and lower.

Third, when it can truly return to the state before the outbreak, it depends on the population's natural infection and the coverage of the immune population.

　　Feng Luzhao also said that the possibility of seasonal onset of new crown pneumonia in winter and spring is not ruled out in the future, but the specific "annual epidemic" or "epidemic once every three years and five years" depends on the population's immunity to the new crown virus.

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