Zhong Nanshan, academician of the Chinese Academy of Engineering and director of the National Clinical Research Center for Respiratory Diseases of the First Affiliated Hospital of Guangzhou Medical University, has long been committed to the research, prevention and treatment of major respiratory infectious diseases and chronic respiratory diseases.
Gu Dongfeng, academician of the Chinese Academy of Sciences and acting vice president of Southern University of Science and Technology, is mainly engaged in the epidemiology, population prevention and control and genetic etiology of chronic diseases such as cardiovascular diseases.
Dong Chen, academician of the Chinese Academy of Sciences and professor of Shanghai Jiao Tong University School of Medicine, is mainly committed to the research of immunology.
At present, the emergence of the new crown virus variant Aomi Kerong has added a lot of uncertainty to the global epidemic prevention and control. In the face of the constant emergence of mutated strains, how to make vaccines play a better role in epidemic prevention and control? How can we develop a vaccine that can prevent more diseases? When will people's lives return to normal?
Recently, the second Greater Bay Area (Shenzhen) Vaccine Summit was held in The form of "online + offline" in Shenzhen Pingshan and Beijing respectively. At the meeting, Zhong Nanshan, academician of the Chinese Academy of Engineering, Dong Chen, academician of the Chinese Academy of Sciences, Gu Dongfeng, academician of the Chinese Academy of Sciences, and many other experts analyzed the current situation and future trend of the global epidemic.
Zhong Nanshan:
Prevention is still the best way to prevent and control the new crown epidemic
The Omikejong variant has emerged, is it necessary to replace the strain for the development and vaccination of related vaccines?
Zhong Nanshan pointed out that whether to replace the strain depends on two factors, one depends on the spread of Aomi Kerong, and the other depends on the pathogenic rate of Aomi Kerong, to see whether its pathogenic rate is as terrible as people think.
How good is Omicron? "In terms of genetic sequence, Delta has 3 mutation sites, while Omilon has as many as 15." Zhong Nanshan introduced that this suggests that the Aomi Kerong strain is more contagious, and as for the pathogenic rate, there are now different views. In the current situation in countries such as South Africa, at first glance, most patients have mild symptoms.
"I don't think it's time to adjust [the strain], but I need to look at the development trend of the Omiljun virus." Zhong Nanshan analyzed that although the protection rate of inactivated vaccines is slightly lower, it has the widest coverage. Based on this year's study on the outbreak of the new coronavirus Delta strain in Guangzhou, the preliminary statistics of the vaccine protection effect are 59%, and 100% can prevent severe disease, indicating that domestic vaccines are useful.
What is the protection rate of existing vaccines? Will the neutralization ability of existing antibodies to Omexjong be reduced? Zhong Nanshan said that it is now being intensively studied and still needs to be observed. "But no matter what, we apply this dynamic zero-zero response, and adopt further precision prevention and control, and we don't have to be afraid of Aumey kerong." Moreover, in the world, many countries have paid more attention to this situation. Zhong Nanshan said that prevention is still the best way to prevent and control the new crown epidemic.
Zhong Nanshan pointed out that although the vaccine has obvious effects in the prevention and control of the new crown virus, especially in the prevention of severe diseases, whether it is an inactivated vaccine or an mRNA vaccine, after a full course of treatment, the humoral immune function of the body has decreased significantly (the situation of cellular immune function is still being collected and observed), so countries are exploring how to strengthen immunity.
After receiving two doses of the vaccine, does the "booster" vaccine work? In this regard, Zhong Nanshan said that after two doses of inactivated vaccination, the third dose of the original vaccine is effective and has proved to have clinical protection enhancement in the real world. At the same time, after two doses of inactivated vaccination, mRNA vaccine, subunit protein vaccine, and adenovirus vector vaccine were effective. Vaccination against xenotype vaccines may be more effective, but their protection rates need to be further observed in the real world to confirm.
Zhong Nanshan introduced that the World Health Organization summarized that there are four main attitudes of different countries to treat the new crown pneumonia epidemic: one is strong control; the second is suppression; the third is containment; and the fourth is not to take effective measures. China adopts strong control and implements a strategy of fine landing to community dynamic zeroing.
"Since 2020, China has had the lowest prevalence and mortality rate of COVID-19 in the world." Zhong Nanshan pointed out that this is due to our prevention-oriented strategy of doing "upstream": community prevention, early detection, early diagnosis, early treatment, and early isolation.
"Since mid-to-late March last year, we have been able to control the epidemic very well." Zhong Nanshan said that after about 20 months, from the recovery of the economy to the resumption of work and school, China has done quite well in the world, and now some countries are also learning from China's strategy.
How can people's lives return to normal?
Zhong Nanshan believes that this requires two prerequisites: one is that the case fatality rate should drop to about 0.1%, which is basically the level of influenza, but it is still above 1% in the world; the second is that the replication index is about 1-1.5.
To this end, we must adhere to three prevention and control measures: the whole people are vaccinated and herd immunity is established; the normalization of community group prevention and group control; and the development of effective therapeutic drugs.
Zhong Nanshan revealed: "The case fatality rate of the Delta virus outbreak in Guangzhou and Nanjing this year is zero, which is very related to vaccination. Now we need to pay attention to the need to strengthen the vaccination of the elderly, especially the elderly over 70 years old. Zhong Nanshan stressed that some elderly people feel that the impact of not vaccinating is not great because they go out less, and in fact, they should strive to do their best.
Gu Dongfeng:
Older people in particular need to increase vaccination rates
The survey results show that all people of the new crown virus are susceptible, but the elderly and patients with chronic diseases are more likely to develop severe pneumonia after infection.
Why is COVID-19 more harmful to the elderly than other age groups?
Gu Dongfeng said that with the increase of age, the physiological functions of the elderly are degraded, the ability to resist infectious diseases is not as good as that of young people, and the probability of suffering from basic cardiovascular and cerebrovascular diseases or a series of other neurological diseases is much higher than that of young people, and the risk of morbidity and death is much higher. For domestic populations, older people in particular need to increase vaccination rates.
According to reports, in the case of the recovery of new crown pneumonia in Wuhan from December 2019 to January to April 2020, the elderly over 60 years old, especially those over 65 years old, some people who originally have underlying diseases such as diabetes, hypertension and coronary heart disease, are prone to cardiovascular inflammation and systemic inflammation after suffering from new crown.
"With underlying medical conditions, coupled with treatment of lung infections, such as lung ventilation, oxygen, and some hormones, the mortality rate is higher in this part of the population." Gu Dongfeng introduced that in addition to the new crown pneumonia, the elderly population is also a susceptible group of avian influenza and influenza.
Large sample data show that vaccination is very effective in protecting both young and old people. "Therefore, some countries will give priority to immunotherapy for the elderly over 60 years old when the vaccine is relatively tight." Gu Dongfeng said that in patients with underlying diseases such as cardiovascular and cerebrovascular diseases, after conducting clinical trials related to new crown pneumonia and influenza, the risk of death in patients with hypertension, diabetes and coronary heart disease will be reduced.
Dong Chen:
Focus on protecting people who are more susceptible to the virus
At present, neither through infection nor vaccine can induce a very strong immune response, and the mutated virus can still break through the immune barrier. Is there any hope that stronger vaccines that can interrupt transmission be developed?
In this regard, Dong Chen said that this may be related to the uneven immune response of different people to viral infections. The study found that, on the one hand, there is still a certain humoral immune response in severe patients, but there are still large defects in cellular immunity, including the number of T lymphocytes and antigen virus-specific responses. This requires that when designing vaccines and monitoring the immune barrier, not only the production of antibodies, but also the immune response of T cells.
On the other hand, in practice, the vast majority of infected people are asymptomatic or mild, and some of them will become severe, which shows that the response of the population to the virus is uneven, indicating that the human body's response to the virus is not simple and stylized, but related to each person's physique, genetic background, environmental factors, age, etc.
From this point of view, "we need to focus on protecting people who are more sensitive to the virus." Dong Chen believes that if it is found in time that there is no good immune protection after vaccination, it is necessary to supplement the vaccination in time, including injections, so that they can further improve immune protection, which is very meaningful for blocking the spread of the virus.
Dong Chen suggested that we should take advantage of the opportunity to study the new crown virus vaccine and compare the immunization mechanisms caused by different vaccine pathways, which is of great significance for the future to develop a good vaccine in a timely and targeted manner in the face of new variants and new viruses.
"Our current policy is very effective, and we hope that through the continuous vaccination and strengthening, we can improve the immunity of the population." Dong Chen believes that at the same time, through the effective control of public policies, including the people consciously wearing masks, etc., do a good job of self-protection to prevent the spread of the virus, to avoid the virus pandemic, in fact, a two-pronged approach. (Reporter Wang Meihua)
People's Daily Overseas Edition (09th edition, December 10, 2021)
Source: People's Daily Overseas Edition