Gao Fu, director of China CDC: there is no evidence that the new coronavirus can cause ade

category:Health
 Gao Fu, director of China CDC: there is no evidence that the new coronavirus can cause ade


Under normal circumstances, a person infected with the virus, as long as the final recovery, the human immune system will produce antibodies to the virus. In this way, the antibody in the human body can inhibit the infection of the virus and realize immunity. However, in some cases, for example, the virus mutates, and when a person is re infected with the virus, the antibody originally produced by the human body will not work for the mutated virus. And at this time, because the human immune system mistakenly thinks that the virus has been suppressed, it will be completely unprotected against the virus. This can lead to more severe symptoms and more infection in patients infected with the mutated virus than those without antibodies. At this time, the bodys antibodies, on the contrary, will help the mutated virus into the target cells, increasing the infection rate. This phenomenon is called ade effect, which is antibody dependent enhancement effect.

The statement that new coronavirus can cause ade is not rigorous and scientific. First, this is a scientific problem. We should leave it to science and do it slowly. At present, there is no evidence that the new coronavirus can cause ade. Second, we have not seen ade phenomenon in all our studies and clinical trials. For example, secondary infection has been reported in Hong Kong, the United States, the Netherlands and Belgium, but it does not show that secondary infection has ade effect. Third, vaccines are for healthy people. We should be cautious and optimistic. This is the balance between risks and benefits. After our assessment, we think that we still need to vaccinate, but the vaccines to healthy people should be safe, effective and controllable. Gao Fu, director of China CDC, told first finance and economics.

If ade appears in the new coronavirus, the current research and development of new coronavirus vaccine and new coronavirus antibody drugs will be stopped. In fact, none of this happened.

Ade is the biggest obstacle in vaccine development. On August 14, 2020, the drug evaluation center of the State Drug Administration issued the technical guidelines for research and development of new type of vaccine for prevention of coronary pneumonia, which pointed out that safety is the top priority in vaccine research and development, and the benefits from vaccine effectiveness must be far higher than the losses caused by adverse reactions, and ade is not acceptable.

When we developed the new crown vaccine, we did this research, and the data showed that the risk was very small. A staff member involved in the development of new crown inactivated vaccine said.

Re infection with new coronavirus is a good case to observe ade effect.

On August 24, researchers at the University of Hong Kong reported the worlds first confirmed case of repeated infection with the new coronavirus. The new coronavirus was not the same before and after the patient was infected, the paper said.

The patient did not have ade and was asymptomatic during the second attack. According to previous studies, rhesus monkeys also showed mild symptoms during reinfection, so the researchers believe that the reduction of re infection symptoms may be related to the initiation of adaptive immunity in patients with initial infection. Although the novel coronavirus pneumonia does not prevent the patient from reinfection, it still shows the effect of protecting the patient from the symptoms of the new crown pneumonia.

Ade in the history of vaccines

So has ade occurred in the past vaccine research and use?

The first is the emergence of new vaccines for SARS and coronavirus in clinical trials There are also concerns in the academic community. In the near future, such concerns are gradually diminishing. The virology experts said.

The expert said that on the one hand, inactivated vaccines, mRNA vaccines, vector vaccines and other new coronavirus vaccines with multiple technical routes have completed the challenge test of primates, and none of them has observed ade phenomenon; on the other hand, some researchers have carried out systematic analysis on animal experiments in which ade phenomenon has been observed, and the conclusion is that these studies have obvious differences in methodology and mechanism research The indication of the results is very limited. The obvious counter example is that many vaccines, including influenza vaccines, have been observed in laboratory studies, but have not occurred in the use of hundreds of millions of people. Experts explained that for the new vaccine, the sample size is always limited in the clinical trial stage, and it is impossible to completely exclude all the safety risks. The results of short-term animal challenge test after vaccination, long-term animal challenge test after vaccination (antibody level decreased significantly), and phase III human protection efficacy test will provide more convincing evidence. Vaccine use strategies can be flexibly formulated based on different evidence strength. Source: editor in charge of the first finance and Economics: Wu Yanli_ NBJS6202

The expert said that on the one hand, inactivated vaccines, mRNA vaccines, vector vaccines and other new coronavirus vaccines with multiple technical routes have completed the challenge test of primates, and none of them has observed ade phenomenon; on the other hand, some researchers have carried out systematic analysis on animal experiments in which ade phenomenon has been observed, and the conclusion is that these studies have obvious differences in methodology and mechanism research The indication of the results is very limited. The obvious counter example is that many vaccines, including influenza vaccines, have been observed in laboratory studies, but have not occurred in the use of hundreds of millions of people.

Experts explained that for the new vaccine, the sample size is always limited in the clinical trial stage, and it is impossible to completely exclude all the safety risks. The results of short-term animal challenge test after vaccination, long-term animal challenge test after vaccination (antibody level decreased significantly), and phase III human protection efficacy test will provide more convincing evidence. Vaccine use strategies can be flexibly formulated based on different evidence strength.