Although the current new crown epidemic is still showing a global epidemic and a partial rebound. However, as the new crown vaccine has been put into use around the world, this fight against the epidemic has finally ushered in the dawn of victory.
According to statistics from Sina Pharmaceuticals, as of the middle of last month, there are 9 types of new coronavirus vaccines that have been marketed worldwide. The research and development institutions of these vaccines are:
mRNA vaccine: Pfizer, Moderna
Adenovirus vector vaccine: Russian Satellite V, AstraZeneca/Oxford, Johnson & Johnson, Can Sino
Inactivated vaccines: Kexing, Beisheng Institute of Sinopharm, Wuhan Institute of Sinopharm
In my country, there are currently 5 new coronavirus vaccine developers that are conditionally listed or approved for emergency use, including:
Inactivated vaccine: Kexing, Beisheng Institute of Sinopharm, Wuhan Institute of Sinopharm
Adenovirus vector vaccine: Can Sino
Recombinant protein vaccine: Zhifei Bio
On the whole, the new coronavirus vaccines currently on the market mainly focus on the technical routes of inactivated vaccines, recombinant protein vaccines, vector vaccines (such as adenovirus vector vaccines), and nucleic acid vaccines (such as mRNA vaccines). These vaccines include the first First, second, and third_generation vaccine technology. It can be seen that the current vaccine technology upgrade is at the node of the second-generation vaccine to the third-generation vaccine. The research and development of the new crown vaccine have accelerated the application and maturity of the third-generation vaccine technology.
It is reported that a data from the new crown vaccine tracker shows that as of 8 o'clock on April 23, Beijing time, the cumulative number of new crown vaccines in the world is about 950 million. According to the latest statistics, my country has received more than 200 million doses of the COVID-19 vaccine.
It is worth noting that, contrary to the constant negative news about new coronavirus vaccines abroad, the new coronavirus vaccines currently on the market in my country have shown good safety. Previously, the relevant competent department of the National Health and Medical Commission stated that no matter what technical route is adopted, as long as the country has formally approved a vaccine with conditions for marketing, its safety and effectiveness are supported by certain data, and the potential or known benefits are greater than the potential. Risks or known risks, the public can rest assured to choose.
But at the same time, because of the tight demand, people in many areas in my country have reported that it is difficult to make an appointment for the second dose of the new crown vaccine. Under such circumstances, single-dose vaccination programs have attracted more and more attention.
The recombinant new coronavirus vaccine (adenovirus vector type 5) (Ad5-nCoV) developed and produced by CanSino Bio is currently the only single-dose new coronavirus vaccine approved in my country. It is believed to achieve faster immune protection and shorten the vaccination cycle. The realization of herd immunity in a shorter time provides a strong guarantee.
Interim data from the global phase III clinical trials of the vaccine show that the overall protective efficacy against all symptoms is: 65.28% after 28 days of single injection and 68.83% after 14 days of a single injection. The protective effects against severe illnesses were: 90.07% after 28 days of single-dose vaccination; 95.47% after 14 days of single-dose vaccination.
Recombinant new coronavirus vaccine (type 5 adenovirus vector) is a "net celebrity" vaccine that has attracted much attention from the beginning of its research and development-this technological path once became famous in the fight against Ebola virus; followed by my country's first COVID-19 vaccine to enter clinical trials, and the world's first COVID-19 vaccine to enter phase I and II clinical studies.
Then, as more and more new crown vaccines become popular, we need to understand more clearly——
What is a vaccine? What is the real role of the vaccine?
What is the difference between these technical paths of the new crown vaccine? What are the characteristics and advantages?
Can the adenovirus vector vaccine that has received much attention be able to overtake in a curve and become a "sword fighter" for mankind to fight the epidemic?
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What is a vaccine? What kind of changes and upgrades have you experienced?
Vaccines are autoimmune preparations made of pathogenic microorganisms (such as bacteria, rickettsiae, viruses, etc.) and their metabolites through artificial attenuation, inactivation, or genetic modification, etc., to prevent infectious diseases.
For hundreds of years, the evolution of vaccines has undergone one, two, and three generations of upgrading and evolution: inactivated, attenuated, or non-toxic complete pathogens (whole vaccines)-subunit vaccines and genetically engineered vaccines, etc.-nucleic acid vaccines (DNA vaccine, genetic vaccine).
The first generation of vaccines used intact pathogens as vaccines. Simply put, the virus was directly used to kill the virus or reduce its toxicity so that when the vaccine enters the body, the human body produces antibodies to achieve the purpose of immunity.
The second-generation vaccine reduces the antigen to the protein or polysaccharide of the pathogen. The antigen design can be realized through gene recombination technology, and the antigen can be expressed and purified in vitro. Compared with the first-generation vaccine, the second-generation vaccine is safer and has lower toxic and side effects.
The third-generation vaccine simplifies the antigen into a top-level nucleic acid substance and uses human cells to achieve one-step intracellular antigen expression after vaccination. At present, the third-generation vaccine has obvious advantages in R&D speed, industrialization, and vaccine immunogenicity, and its application prospects are good.
Judging from the world’s fastest-growing and most effective new coronavirus vaccine, in addition to inactivated vaccines, which are traditional vaccines, the third-generation vaccines represented by mRNA nucleic acid vaccines and adenovirus vectors are the most prominent.
Among them, mRNA vaccines belong to nucleic acid vaccines, which is a brand-new technical route. This kind of vaccine refers to the in vitro synthesis of virus-related sequence mRNA delivered to human cells to form an immunity.
The advantages of mRNA vaccines are rapid development and higher protection rates. But its disadvantage is that the reliability has not been fully verified. Beside, mRNA vaccines have strict requirements on storage and transportation temperatures. There are currently two mRNA vaccines on the market around the world, one is the mRNA vaccine of BioNTech, Pfizer, Pfizer, and Fosun Pharma; the other is the mRNA vaccine of Moderna.
Adenovirus vector vaccine belongs to the vector vaccine in new vaccines. It uses adenovirus as a carrier to recombine protective antigen genes into the adenovirus genome. Compared with ancient attenuated or inactivated vaccines such as vaccinia, carrier vaccines have sufficient safety and can produce good immune effects.
Some experts said: "Compared with inactivated vaccines, the advantage of carrier vaccines is that they can induce better cellular immunity. One is to produce better long-term memory, including the production of more affinity antibodies; the other is to produce specific killer cells. Immunization is used to remove infected cells. Compared with mRNA vaccines, viral vector vaccines can generally be stored at 2-8 degrees Celsius for more than 12 months, which is easier to store and transport, and can maximize the availability of vaccines. The carrier vaccine has the same mechanism of action as the mRNA vaccine, but the safety is better."
Why do adenovirus vectors play an important role?
With the release of the latest clinical data of CanSino's recombinant new coronavirus vaccine (type 5 adenovirus vector), the adenovirus vector new coronavirus vaccine has once again received widespread attention and high hopes.
So, with so many viruses, why is it an adenovirus?
In the book "Principles of Genetic Engineering" published at the beginning of this century, Professor Wu Naihu from the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences mentioned foresight: Adenovirus has great potential, and its outstanding characteristics are (the head and tail ends). ) With inverted terminal repeats. That is, as long as one section (head or tail) is complete, the other section can be restored even if it is missing, just like the regenerative ability of a gecko, so that the adenovirus can be cut and assembled according to the wishes of humans and expressed as usual. The function is simply a "weapon" in the field of genetic engineering.
A few years later, the adenovirus vector has indeed repeatedly provoked an important task in the epidemic crisis that mankind has not encountered in a century.
It has shined in the fight against the Ebola epidemic and has been widely used in the research of human immunodeficiency virus (HIV), influenza virus, Plasmodium falciparum, Mycobacterium tuberculosis, hepatitis C virus, and other vaccines.
The recombinant adenovirus vector neocoronavirus vaccine is to use the modified replication-deficient adenovirus as a carrier, carry the neocoronavirus S gene, and enter the subject so that the human body can produce immune memory of the S protein, thereby achieving immune effects.
An image metaphor is that the adenovirus vector is like a "truck" carrying the S gene of the new coronavirus, delivering the target gene into the cell, guiding the host cell to translate the S protein that people want, and allowing the immune system to recognize it. When encountering the new crown virus, they can immediately organize a counterattack.
Single-dose Ad5-nCoV vaccine, the next strongest first choice?
Among the adenovirus vectors, especially the human type 5 adenovirus vector (Ad5) is the most widely used. Relying on this technology, CanSino Biosciences successfully developed a recombinant Ebola virus disease vaccine in 2017 with the Academy of Military Sciences. Based on its safety has been confirmed, after the outbreak of the new crown in 2020, CanSinoBio quickly launched the research and development of the adenovirus vector new crown vaccine.
On March 16, 2020, the recombinant new coronavirus vaccine (type 5 adenovirus vector) will start a phase I clinical trial in Wuhan. It is the world's first COVID-19 vaccine to enter clinical trials.
On April 12, 2020, the recombinant new coronavirus vaccine (type 5 adenovirus vector) vaccine started a phase II clinical trial in Wuhan, and it was the world's first phase II new coronavirus vaccine to enter the clinical research phase.
The results of Phase II clinical trial of the vaccine showed that after 28 days of a single vaccination of the adenovirus vector COVID-19 vaccine, 97% of the subjects developed specific antibodies and 88% of the subjects developed specific cellular immunity. This shows that one shot of vaccination can provide humoral immunity (antibody) and cellular immunity, giving the subject double protection.
On August 16, 2020, the recombinant new coronavirus vaccine (type 5 adenovirus vector) was granted a patent in my country, becoming China's first new coronavirus vaccine to obtain a patent for invention.
On January 14, 2021, the interim results of the Phase III clinical trial of the recombinant new coronavirus vaccine (type 5 adenovirus vector) in Russia showed that 92.5% of Russian volunteers showed high antibody levels and did not produce Serious side effects.
On February 25, 2021, the conditional marketing application of the recombinant new coronavirus vaccine (type 5 adenovirus vector) has been approved by the National Medical Products Administration.
According to the “Introduction to Target Products of New Coronavirus Vaccine” previously released by WHO, the ideal standard for vaccination procedures is single-dose vaccination during the outbreak period.
Another WHO paper published in the New England Journal of Medicine stated: "A vaccine with a single-shot protection effect of about 70% is more valuable than a two-shot vaccine with a protective effect of 90%."
With the same technical path and production capacity, a single-dose vaccine can double the coverage of the population, and at the same time, the burden on medical institutions and the expenses that patients need to pay will be at least halved.
Undoubtedly, the launch of the recombinant new coronavirus vaccine (type 5 adenovirus vector) will definitely make a big mark in the global fight against the epidemic.
From the perspective of fighting the epidemic, the new crown epidemic has an extremely rapid and large-scale impact that has caused many parts of the world to fall into a stage of stagnation and regression while suffering from the epidemic. Many countries have stopped production, foreign trade, and foreign trade due to phased shutdowns. The economic development has been hit hard by factors such as traffic obstruction. While the recombinant new coronavirus vaccine (type 5 adenovirus vector) brings new hope and confidence in the global fight against the epidemic, it will also contribute to China's strength in the recovery of the global economy.
From the perspective of research and development strength, in this global competition, the recombinant new coronavirus vaccine (type 5 adenovirus vector) has emerged in the clinical trial stage, and now the efficacy is not disappointing, demonstrating the power of China's vaccine innovation.
Beside, from the perspective of industrial upgrading, the current global vaccine research and development is still using the second-generation vaccine as the mainstream of vaccine research and development. There is a clear gap in the second-generation vaccine in China, and the research and development of the new crown vaccine have accelerated the application and maturity of the third-generation vaccine technology.
In the global three-generation vaccine race, Chinese vaccines and Chinese vaccine companies, represented by recombinant new coronavirus vaccines (type 5 adenovirus vectors) and companies such as Cansino, are rapidly becoming the world’s first echelon and are expected to welcome them. The watershed for the development of China's vaccine industry.
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