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The vaccine has to successfully stimulate the organism to produce an immune response in order to clear the virus. So, how does one make a good vaccine?
"Biology is complex, and the best way to do that is to follow nature, which is to understand how a recovering patient clears the virus, Simulating the process is the best route to take, and their success is what guides us." Lu Mengji, a Chinese virologist and professor at the Institute of Virology at the University of Essen Medical School in Germany, said at a forum recently.
In Lu Mengji's view, the current vaccine progress is still only the first step in the "10,000-mile march". "(Because) time is relatively short, it's not clear enough to understand how a patient clears the virus, and there's a lot of uncertainty." Lu Mengji confessed.
The battle between humanity and the new coronavirus is shifting towards "protracted warfare", with vaccines considered to be the best "weapon" to end the battle.
According to an article published in Nature Reviews - Drug Discovery by the Coalition for Innovation in Epidemic Prevention (CEPI), as of April 8, 2020, the global picture of novel coronavirus vaccine development included 115 vaccine candidates, 78 of which were confirmed to be in advanced status.
It is worth looking forward to the fact that three vaccines have entered clinical trials in China. Including the fastest-growing adenovirus vector vaccine from the team of Academician Chen Wei of the Institute of Bioengineering, Military Medical Research Institute, Military Academy of Sciences, the world's first new coronavirus vaccine species to enter Phase II clinical studies.
In addition, a new coronavirus inactivation vaccine jointly applied for by China Biological Wuhan Biological Products Research Institute of Sinopharm and Wuhan Institute of Virus Research of the Chinese Academy of Sciences has also entered Phase I and Phase II combined clinical trials.
The inactivated vaccine developed by Beijing Kexing Zhongwei Biotechnology Co., Ltd. was also approved for clinical trials.
Clinical trials are an essential and critical part of the pre-marketing of vaccines and typically require Phase III clinical trials.
Lu Mengji said that the first phase is a safety evaluation, which mainly recruits a portion of healthy people to test to see what adverse reactions there are.
"(Many clinical trials of vaccines) 'die' in Phase II, and one or two successes in 100 would be nice." Lu Mengji said that the Phase II trial, which focuses on testing effectiveness, will test the immune response and protective properties of the vaccine against the target population.
Phase 3 then expands to more diverse groups of people, including the elderly, children, etc. (This is when it becomes apparent that) different people react very differently, and for some people there may be no protection at all.
"The current (Phase II, III clinical trials) are at the most difficult 'over the grass' stage."
Lu Mengji said that adverse reactions are a relatively important indicator of vaccine success. "The biggest adverse reaction, and the thing we're most worried about, is that there will be an antibody enhancement effect."
Typically, after a vaccination, the body produces antibodies to fight off the virus, making it impossible to infect other cells. However, in some cases, the antibodies do not completely kill the virus.
The original neutralizing antibodies not only cannot prevent the virus from invading human cells but can interact with Fc receptors or complement to invade monocytes, granulocytes, etc., enhancing the replication of the virus in the body and causing serious pathological reactions.
"This process, if severe, can cause a large area to be infected, most typically with the dengue virus. Therefore, vaccines, especially those that focus on stimulating antibody responses, must exclude antibody-enhanced responses 100% of the time." Lu Mengji said.
Indeed, vaccines are difficult to develop, have long lead times, and have high failure rates. It is understood that at the end of 2018, only 77 preventive vaccines had been approved globally for 41 diseases.
"It's not easy to make a good vaccine, most of it costs money. It can be seen that in the marketplace, people think vaccines are very important, but they don't want to do them." Lu Mengji said.
Lu Mengji described Germany's approach to the development of new coronavirus vaccines as a mechanism of scientific research, development, company, management and national division of labor: first, scientific units provide basic information about the vaccine; specialized companies use their technology platforms and professionals to implement it according to the indicators provided by the scientists; then, traditional vaccine manufacturing companies conduct mass production; and the regulatory bodies provide special approval.
"Normally, it takes 10, 20 years for a vaccine to go from research to market, and now we want to go through (the whole process) in 18 months, but the research and development process is very difficult to shorten, and the standards of the governing bodies do not drop, and the timeline is not shortened. The German practice is that after making a vaccine, the traditional vaccine manufacturing company produces tens of millions of copies directly (it also takes months to produce), and in the end, if it doesn't work out, the state pays for it, trading the economic loss for a few months, but it's safe, and the whole management is not less strict."
Lu Mengji said, "Currently, several traditional companies have started full production lines (different production processes for different types of vaccines) and are just waiting for the vaccine to come out."
At present, the global vaccine research and development "a hundred boats vie for the current, a thousand sails race to the top". In Lu Mengji's view, the development of a new coronavirus vaccine is a common global problem, and "in the end, the best vaccine must be developed by all."
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