“Dynamic reset” provides a time window for strengthening vaccination and accelerating the development of drugs and vaccines.
Writing | Yan Xiaoliu Source | “Medical Community” official accountlocal time on May 10 , World Health Organization(WHO) Director-General Tedros Adhanom Ghebreyesus commented on the “zero strategy” and said: “The new coronavirus continues to evolve and is becoming more contagious, so changing The response will be very important. The WHO believes that countries now have a better understanding of the new crown virus, and also have good anti-epidemic tools to use, and can transition to new strategies.”Same day, < span>Nature Medicine The latest research such as the School of Public Health of Fudan University is published online , involving several important findings, or pointing out the direction for future epidemic prevention strategies. The results show that, based on the vaccination level of the population in my country in March 2022, the resulting immune barrier cannot effectively prevent the peak of Ommikron infection. If China does not adopt a “dynamic clearing” strategy, Omicron will cause a severe burden of new crown infections, leading to exhaustion of medical resources and runs on intensive care(ICU). By then, the demand for ICUs by patients will rise to 15.6 times the number of existing beds, and the shortage of ICU beds will last for 44 days, possibly resulting in 1.55 million deaths. “Each country should be prepared to chart its own path from a pandemic phase to an endemic phase. This requires consideration of local epidemiology, vaccination levels, population immunity and Health system strength.” The study stated that “walking on three legs” will be the focus of future epidemic prevention and control, including universal vaccination, improving access to antiviral treatment, and maintaining non-drug public health interventions (NPI) and other comprehensive measures. 
Screenshot from Nature MedicineWith vaccines alone, what will happen to the epidemic in China? The aforementioned research is the latest modeling achievement of Yu Hongjie’s team from the School of Public Health, Fudan University. The baseline condition of the model includes six considerations. Including 20 cases of Omicron infection in China on March 1, 2022. The Rt value（Effective reproductive number, effective reproductive number) decreased from 3.9 at the beginning of the simulation to 3.4 after the vaccination rate was improved. Achieve 5 million doses of inactivated vaccine daily. The model also takes into account the immune evasion of variant strains, as well as the efficacy of homologous and heterologous vaccination. And, at baseline, there are no NPI measures such as mass nucleic acid testing and travel restrictions, and no anti-coronavirus treatment. The results show that, without NPI intervention, during the 6-month simulation period(until September 2022), Ormy Keron will cause a domestic “epidemic tsunami”. This is expected to result in 112.2 million symptomatic infections nationwide, 5.1 million hospitalizations, 2.7 million ICU transfers, and approximately 1.6 million deaths. The peak of infections occurred between May and July 2022. 
March 2022-September 2022, modeling the infection burden of Omicron in China under the baseline scenario. /Nature MedicineConsidering age characteristics and vaccine coverage, those 60 years and older are the most affected by the outbreak. More than 90% of ICU cases are concentrated in this age group. Meanwhile, unvaccinated people aged 60 and over accounted for 74.7% of all deaths. A similar trend was observed in the fifth round of the epidemic in Hong Kong SAR. Research points out that China is vast and highly diversified. Diversity is also reflected in vaccination rates, demographics, and the ability of healthcare systems to respond. Considering these heterogeneities, the simulation results found large differences in the burden of COVID-19 in different regions. In the comparison of the three places, the hospitalization rate, ICU rate and mortality rate of people aged 60 and over in Shanghai were higher than those in Shandong and Shanxi. This may be related to vaccination rates in this age group. As of April 15, 2022, 62% of people aged 60 and above in Shanghai have completed the full course of vaccination, and 38% of people in the same age group have completed booster shots. As of March 21, 2022, 89.16% of people in the same age group in Shandong have been vaccinatedVaccines, 72.45% finished booster shots. 
Infection outcomes by age group, from top to bottom, were hospitalization, ICU, and death (China overall, Shanghai, Shanxi, Shandong). The /Nature Medicine study also assessed the impact of the Omikron epidemic on the nation’s healthcare system. If it is assumed that all hospitalized patients with new crowns need respiratory beds and all severe cases need to be admitted to ICU, estimates show that at the peak of the epidemic in Omicron, about 1.57 million beds for respiratory diseases are needed nationwide. This is lower than the current 3.1 million in my country. However, the peak demand for ICU beds will reach 15.6 times the number of existing beds in my country, and the shortage period of beds will last for 44 days. 
Demand for inpatient beds and ICU beds per million people under different conditions. /Nature MedicineTwo keys to “COVID-19 down to flu level”What should be the next step for epidemic prevention strategies Sample? Yu Hongjie’s team thought about this issue, and based on the model, they evaluated the impact of three anti-epidemic strategies: first, promoting vaccination, including heterologous boosting based on recombinant subunit vaccine, to promote and above should be accepted. Second, increase the availability of antiviral therapy. Third, take stricter NPI measures. The results show that if the elderly population should receive all the booster shots, the number of deaths can be reduced by 60.8%. All symptomatic patients who use antiviral drugs in a timely manner can reduce 88.9% of deaths. Strict NPI measures such as nationwide school closures and closure of all workplaces are adopted to make the Rt value ≤ 2, and the burden of COVID-19 will also decrease. However, it is worth noting that none of the above three strategies can reduce the number of new crown deaths to influenza levels when used alone(88,000 cases/year), and ICU runs cannot be avoided. It is expected that the peak demand of the ICU will be 1.7-14.8 times the maximum capacity, and the shortage of beds will last for 19-48 days. “According to our analysis, the above 3 strategies should be used synergistically. The focus is on improving vaccination rates for people aged 60 and older and widespread use of antiviral therapy.” The study gave two “target values” :First, significant increase in vaccination rates among older adults(97%). Second, 50% or more of symptomatic infected people can use antiviral therapy. According to the study, if the above standards are met, the peak occupancy rate of the ICU will not exceed the actual carrying capacity, and the total number of deaths from the new crown will drop to a considerable level of seasonal influenza. If the above two conditions are not met, in order to avoid the collapse of the medical system, the epidemic prevention strategy may need to strictly rely on NPI measures to reduce the Rt value to below 2. Relevant measures include closing all schools and workplaces and implementing strict social distancing. “To reduce the Rt value below 2 with strict NPI measures, beyond the forecast window(6 months). Measures were not assessed in this analysis The ultimate impact.” Fudan Research said. In the long run, improving ventilation, strengthening the reserve of intensive care resources, and researching new and efficient vaccines to provide lasting immune protection are important measures. China’s “shortcomings” in epidemic prevention need to be filled as soon as possibleThe aforementioned research has some shortcomings. Including the assumption that the mortality rate will remain unchanged during the forecast period, and the data on antiretroviral treatment by region are not included. From its analysis, it can be seen that the uncontrolled new crown epidemic will pose a huge threat to the medical system. On the same day that the Fudan study was released, Nature Medicine also published a large retrospective study from Imperial College London, which also put forward similar views. The results show that about half of COVID-19 deaths could have been avoided without pre-pandemic geographic inequality and COVID-19 runs on health care systems. Especially in low- and middle-income countries, greater investment in healthcare facilities, medical resources, and infectious disease preparedness can minimize the rise in population-wide mortality from highly contagious and deadly pathogens. The Fudan study once again revealed the shortcoming of China’s epidemic prevention: the slow-growing vaccination rate of the elderly. “The virulence of the Omicron variant has decreased and the transmission has been greatly improved. It is expected that by the second half of this year, the vaccine will have more limited significance for young people, and the key to reversing the ‘war situation’ lies in the elderly group .” Combined with the fifth wave of the epidemic in the Hong Kong Special Administrative Region, virology expert Chang Rongshan told the “medical community”. On April 29, at a press conference held by the State Council Information Office, Liang Wannian, head of the expert group of the National Health Commission’s Leading Group for Epidemic Response and Disposal, said:my country’s “one “Old and young” vaccination rates are generally not high enough. In the face of the repeated impact of the new crown pneumonia epidemic, if the so-called “lying flat” strategy of coexisting with the virus is adopted, medical and health resources will face a serious risk of running on health care resources. A large number of patients with underlying diseases, the elderly, children, pregnant women and other groups of people are in good health. will be threatened. At the same time, it will also have a serious impact on economic and social development. “Dynamic clearing” sets aside a time window for strengthening vaccination and accelerating the research and development of drugs and vaccines. Source:[1]Modeling transmission of SARS-CoV-2 Omicron in China.Nature Medicine.doi .org/10.1038/s41591-022-01855-7(2021)[2]Spatial and temporal fluctuations in COVID-19 fatality rates in Brazilian hospitals.Nature Medicine.doi.org/10.1038/s41591- 022-01807-1[3] WHO: The global anti-epidemic status is not optimistic. United NationsSource: Medical communityEditor in charge: Zheng HuajuProofreading: Zang HengjiaPast IssuesWonderful ReviewShanghai has achieved phased results: the social aspects of the six districts are basically clearedThe number of new additions in Shanghai has declined, and it is far from the “social zero” How far is it? Is there a third way between “clearing” and “lying flat”? * The medical community strives for the accuracy and reliability of its published content when it is reviewed and approved, but does not make any commitment to the timeliness of the published content, and the accuracy and completeness of the cited materials (if any), etc. and warranties, and disclaims any liability arising out of the outdated content, possible inaccuracies or incompleteness of the materials cited. Relevant parties are requested to check separately when adopting or using it as a basis for decision-making. 
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