疫苗 z-bo 2020-09-19 385

　　This study is controversial because it uses chickens for testing. Some scientists believe that chicken vaccination has little to do with humans. They worry that this result will raise public doubts about the value and safety of the vaccine. Andrew Reid, a biologist at Penn State University Park, who is in charge of the project, said the above concerns are invalid because the study does not support any form of anti-vacuum movement. However, research results indicate that some vaccines need to be closely monitored or other protective measures need to be taken to avoid abnormal reactions.

　　From an advanced chemical point of view, many pathogens are less lethal or toxic, because early killing of the host does not allow them to spread among the infected. However, some vaccines cannot prevent pathogen infection, but they can help reduce the severity of the patient's condition. 14 years ago, Read first announced in the journal Nature that these "incomplete" or "defective" vaccines actually increased the spread of deadly pathogens by extending the life of the host. Under normal circumstances, the more virulent the pathogen, the shorter the survival time in the host.

　　Recently, Read (Read) published an article that this phenomenon seems to be reflected in Marek's disease (chicken virus disease). The pathogen of Marekella spp. usually lies in a sensitive bird feather bag, while other birds inhale fluffy secretions to spread the infection. Farmers regularly inject disease-resistant vaccines into poultry to ensure their health, but they cannot stop the spread of the virus or the spread of poultry. In the past few decades, the pathogenicity of Marek’s disease has continued to increase, and researchers speculate that this may be the result of vaccination.

　　Ead conducted a chicken pathogenicity study with researchers from the Perbright Institute in the United Kingdom (located in Camptonshire). They selected different types of known virus strains to infect chickens, with their toxicity ranging from low to high. The results showed that the non-blood-sucking chickens died soon after being infected with the highly pathogenic virus strain, resulting in very low virus transmission, several orders of magnitude worse than the low-viral virus group. But for vaccinated chickens, the situation is quite different. Chickens infected with highly virulent viruses will spread more viruses. In addition, the researchers also found that when a healthy herd is mixed with unvaccinated and vaccinated chickens with a high virulence virus, the results will be different. .. The former is still dying rapidly, which shows that healthy chickens are safe and the disease is unlikely to spread. The latter survived longer, so "cage friends" were infected and died. Therefore, vaccination promotes the continued spread of the virus, and people who have not been vaccinated face the threat of serious illness and even death. The research results were published online in the PLOS Biology Journal of the Public Science Library on July 27.

　　Michael L from the University of Cologne, Germany? ssig is a physicist who studies the evolution of influenza. He pointed out that the results of this study are credible, but due to the background of its specialized research, it is still necessary to be cautious in drawing general conclusions.

　　Adrian Hill, a vaccine researcher at the University of Oxford in the United Kingdom, supports the speculation that the above experiment "promotes the development of the more deadly Marek's disease", but it has been strictly proven. Say no. In addition to Marek's disease, many other factors have also affected the development of the poultry industry in recent decades. For example, the year-on-year expansion of the scale of production may lead to the propagation of more virulent virus strains. But Reid said that if a person stops vaccinating, those so-called virulent strains will soon disappear. Hill believes that certain defective vaccines will enhance the ability of this virus, but the real question before him is how this process occurs. They have been studying this problem for 15 years and only found one example. Therefore, he believes that the public need not worry too much about this.

　　Ead regrets that there are other examples to explain this phenomenon. Calicivirus disease in cats may be another good example. Reid said it can cause airway infections in cats. I am particularly worried about bird flu. In the United States and Europe, flu outbreaks usually kill poultry, so further outbreaks of the virus are unlikely, but Asian farmers often choose to use vaccines and the virus as protective measures. Opportunities are being provided. It evolved into a highly virulent virus strain. Ab Osterhaus, a virologist at the University of Rotterdam in the Netherlands, pointed out that although the possibility of an outbreak is very small, unfortunately, this possibility cannot be completely ruled out.

　　So how do vaccines affect human diseases? Most human vaccines used today are complete and can prevent the spread of diseases. However, when vaccine developers encounter uncontrollable diseases (such as malaria and AIDS), they have strict requirements on the quality of vaccines, hoping that they can prevent the disease from worsening rather than prevent infection. cut back. We point out that we have entered an era of universal access to defective vaccines. Not long ago, European authorities approved potential vaccines against Ebola and malaria and entered the next phase of clinical trials. If the safety and effectiveness are confirmed, it is expected to be put into practical use. But at the same time, it may also lead to the emergence of highly virulent strains. Therefore, Read believes that the use of vaccines requires caution. Hill said the comment itself is irresponsible. ead should stop this vigilance immediately, because there is no evidence in Read that it is an Ebola vaccine or other human vaccines. When used, it produces more deadly pathogens. Hill believes that the strict classification of vaccines into "complete vaccines" and "incomplete vaccines" is inherently problematic. There is no complete vaccine because the effectiveness of the vaccine varies from person to person. In addition, millions of people around the world are vaccinated every month, and there are no relevant reports that vaccination will make the disease more deadly.

　　Supplement, this is like the effect of natural immunity. After recovering from the disease, our body's defenses against specific pathogens are usually incomplete and limited, and the efficacy of vaccines is roughly the same. Africans are immune to all infectious diseases like sea water. When it comes to malaria, no matter how the current vaccine works, its impact will only fall into the ocean. Hill worried that Reid's research would give anti-vampires a chance. Ryder replied that even though human vaccines can cause the evolution of the pathogen "demon", this is not a reason not to withdraw. The key is to carry out vaccination to achieve the effect of joint control of the spread of the disease, supplemented by other means (such as the use of mosquito nets to reduce the spread of malaria).

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　　ead statement is ironic that as pathogens become more pathogenic, they need to be vaccinated to protect themselves from deadly pathogens. This is the story between chicken and Marek's disease. He still believes that the vaccine is the culprit responsible for the super-strong virus strain, but he does not deny that the vaccine has made a huge contribution because even fragile chickens can be protected.