Recently, the State Council Joint Prevention and Control Mechanism Scientific Research and Tackling Group released: two inactivated neo-coronavirus vaccines in China were granted clinical trial approval by the State Drug Administration for a combined phase I and II, and related clinical trials were started simultaneously. This is the first batch of inactivated neo-coronavirus vaccines to receive clinical research approval.
Up to now, three new coronavirus vaccines have been approved to enter clinical trials in China, namely: the adenovirus vector vaccine developed by the team of academician Chen Wei of the Academy of Military Sciences, which was the first to be approved to start clinical trials on March 16 this year; the inactivated new coronavirus vaccine developed by the Wuhan Institute of Biological Products of China, which was approved to enter clinical trials on April 12 this year; and the inactivated vaccine developed by Beijing Kexing Zhongwei Biotechnology Co. Ltd. was approved to start clinical trials on April 13 this year.
At present, there are five technical routes for China's new crown vaccine research, namely: inactivated vaccine, recombinant subunit vaccine, adenovirus vector vaccine, attenuated influenza virus vector vaccine and nucleic acid vaccine. The five vaccines produced by these five technical routes are both the application of traditional technologies, such as inactivated vaccines and subunit vaccines, and the application of new technologies, such as live vector vaccines and nucleic acid vaccines.
So, what is an inactivated vaccine? What is the reason for having two new inactivated coronavirus vaccines approved for clinical use in a relatively short period of time?
What is an inactivated vaccine?
Inactivated vaccine is a vaccine made by inactivating artificially mass cultured pathogenic microorganisms (which may consist of whole viruses or bacteria, or their lysed fragments) using physicochemical methods such as heat or chemical agents (usually formalin), so that they lose their infectivity and virulence while remaining immunogenic, and combining them with corresponding adjuvants.
Inactivated vaccines currently in use in China include inactivated polio vaccine, vaccine against pertussis, influenza vaccine, rabies vaccine, inactivated vaccine against hand, foot and mouth disease (EV71), inactivated vaccine against hepatitis A and polysaccharide vaccine against group A influenza. Inactivated vaccines play a very important role in the prevention of infectious diseases in China, and play an irreplaceable and important role in the prevention of major and emerging infectious diseases.
Why have 2 new inactivated coronavirus vaccines been approved to enter the clinic in a relatively short period of time?
There are two main internal and external factors.
Internal factors
are determined by the main characteristics of inactivated vaccines.
(1) Mature technical route and short development time
To prepare an inactivated vaccine, it is necessary to first culture and screen the strains on suitable cells to obtain viruses with high and stable titers representing the antigenic characteristics of the virus, which can be used to establish a seed bank for future large-scale vaccine production. Vaccine candidates are prepared through the process of culture, inactivation and purification. It is the traditional classical way of vaccine preparation and the process is relatively simple.
(2) Safety is guaranteed to a certain extent
The virus is inactivated, destroying its infection and retaining immunity. A good inactivation process can both prevent the virulence of the virus from returning so that it will not replicate in the host and spread to others, and may kill any other biological factors that become contaminants, ensuring the safety of vaccine use.
(3) Good effectiveness
The inactivation process does not change the particle structure of the virus, retains the surface proteins of the virus, and the antigenicity is similar to that of the live virus. Inactivated vaccine is an immune response based on humoral immunity produced by the vaccinator, and the antibodies produced by it can neutralize and remove pathogenic microorganisms and the toxins produced by them, and have a better protective effect on extracellular infections of pathogenic microorganisms.
(4) Easy to preserve and transport
Inactivated vaccines are relatively stable in nature, easy to store and transport, and generally only need to be stored and transported at 2~8℃.
Of course, while we pay attention to the advantages of inactivated vaccines, we cannot ignore their disadvantages, namely: the lack of immunogenicity, which often requires multiple doses of booster; live virus culture requires biosafety conditions at P3 level, and the capacity can be limited.
External factors
Synergy of departments and strong support from management.
At the beginning of the New Crest Pneumonia epidemic, the Party Central Committee attached great importance to the research and development of the New Crest Pneumonia vaccine, and the research and development group was established with the development of the vaccine as the main direction of priority, and the national advantageous units were organized for joint research and development to accelerate the development of the vaccine. The high level and strategic grasp of vaccine development by the national joint prevention and control mechanism is the cornerstone for efficient advancement of the vaccine.
Governments and scientific research management departments at all levels
They actively coordinate multiple departments to give all-round protection and support to the vaccine R&D team to make the R&D work progress more compact and efficient, and help the project to attack and speed up in an all-round and whole-chain way from coordinating resources, project approval, financial support, international cooperation, etc.
Research and development units
The development units of the two new inactivated coronavirus vaccines approved for clinical use have many years of experience in vaccine development and production. The researchers and the expert teams of the collaborating units encouraged each other, cooperated with each other and worked around the clock to complete all the preclinical research work of the vaccines in a short time and with high quality.
Drug regulatory authorities
The local drug regulatory bureau organized sampling, the national drug inspection department quickly carried out simultaneous testing, and the national drug review department quickly conducted review and coordination according to the requirement of "linking research and review and simultaneous review", which greatly promoted the project process.
In short, we firmly believe that with the guarantee of joint prevention and control mechanism, relying on abundant scientific research investment, all-round resource inclination, parallel work on multiple fronts, scientific researchers working day and night, and rolling review and approval by the evaluation agency without interruption, the rapid entry of new crown vaccine into clinical trials and its early release will be expected in the near future.
