The covid-19 epidemic has spread around the world, infecting more than 4 million people and killing more than 300,000, posing a new threat to human health as a new member of the infectious family.The novel coronavirus vaccine is still in the market, which makes people wonder why the development of novel coronavirus vaccine is so slow.
In fact, the novel coronavirus vaccine was developed at a speed beyond imagination.As we all know, vaccine development is a time-consuming, high-risk and high-investment task, which generally involves three steps: pre-clinical research, human clinical trials, and formal promotion and application.
Under normal circumstances, traditional vaccine development can be as short as three to five years, or as long as more than 10 years, depending on the type of virus and the path of technology used.It is expected to take 12 to 18 months for the covid-19 vaccine to be on the market. Compared with traditional vaccines, its development time has been greatly shortened.A vaccine expert told China news service: “we can understand the public’s desire for the vaccine, but we should face up to the objective laws of vaccine development.”
Developing a vaccine will not be easy.In the case of the SARS(severe acute respiratory syndrome) outbreak in 2003, it took researchers 20 months to develop a vaccine that could be tested on humans, but the epidemic was already under control and large-scale clinical trials could not be carried out.This has led to the fact that, 17 years after the SARS outbreak, no vaccine has yet been produced to prevent the SARS virus.A similar situation occurred in MERS (Middle East respiratory syndrome) outbreak in 2013. Until now, researchers have not developed a vaccine or a specific drug for MERS.
Since the outbreak of covid-19, China has developed covid-19 vaccine according to five technical routes: inactivated vaccine, genetic engineering subunit vaccine, recombinant novel coronavirus vaccine (adenovirus vector), attenuated influenza virus vector vaccine and nucleic acid vaccine. At least more than 15 enterprises and research institutions have carried out research on vaccine development.At present, there is a recombinant adenovirus vector vaccine and four inactivated vaccines, which have been successively approved by the state food and drug administration. Phase I and phase ii combined clinical trials were carried out, and a total of 2,575 volunteers were vaccinated.
Globally, as of May 11, 110 covid-19 vaccines in development have been documented on the who website, of which eight have entered clinical trials.Four are from China, three are from the United States and one is from the United Kingdom.Among them, the novel coronavirus vaccine developed by Chen wei, an academician of the Chinese academy of engineering and a researcher of the academy of military sciences, started phase ii clinical trial on April 12, becoming the world’s earliest novel coronavirus vaccine to enter phase ii clinical trial.
On May 15, zeng yixin, deputy director of China’s national health commission, said at a press conference held by the state council information office that China’s covid-19 vaccine research and development is progressing smoothly, and some projects are expected to complete phase ii clinical trials by July.
“The second phase will be followed by the third phase.The second phase is mainly to test the protective effect and initial safety of the vaccine. The third phase requires a larger sample size and higher requirements.”Wang guiqiang, director of the department of infectious diseases at Peking University’s first hospital.
In addition to the long development process, the safety and efficacy of the covid-19 vaccine is also an important reason for the delay in its release.
Currently, there is no commercially available vaccine against coronavirus in the world, and the lack of experience and risk assessment makes covid-19 a challenge for researchers.Zhang xinmin, director of the biological center of the ministry of science and technology, previously stressed that the safety of vaccines, as a special product for healthy people, is the first priority.“Vaccine development must follow scientific rules and strict regulations, and researchers must be given a certain amount of time.”
The first step in developing a new vaccine is to extract a strain of the virus, which has been done at a staggering pace in several research centers in China, according to the report.But this is only the beginning of vaccine development, which will include culturing strains, modifying the virus, attenuating it, animal testing and human clinical trials.
Wang peiyu, deputy dean of the school of public health at Peking University, said that in order to stimulate the production of antibodies, the vaccine must be consistent with the virus in many aspects, but “very virus-like” vaccines into the human body, whether it will cause side effects and how safe it is to be clear.Therefore, to test the safety and efficacy of vaccines, clinical trials are particularly time-consuming.
So when will the covid-19 vaccine actually hit the market?
Gao fu, director of the Chinese center for disease control and prevention, said China may have a vaccine available in September that can be used in emergencies and could develop a vaccine for healthy people by early next year.
Several research and development teams in the United States and Europe are also aiming for emergency authorization this fall, with the vaccine likely to be available in September.
It will be more than three months from now until September, when scientists will have to find enough samples to complete phase ii and iii trials to confirm their safety.Lu shan, former President of the international vaccine society and a professor at the university of Massachusetts medical school in the United States, said that the preparation of vaccines faces many practical problems, such as the traditional phase iii clinical trials that need to target the target population, the huge investment in vaccine research and development, and the complicated discussion process among experts and institutions.When you get a vaccine depends on the balance of four forces: science, technology, regulatory agencies, and social need.
Vaccine experts also stressed that the quality of vaccines remains the top priority, and that avoiding “unresponsive immunity” is the key to vaccine development.In this case, the availability of a covid-19 vaccine will have to wait.