Written by Hyzhou
On January 30, at the press conference of the joint prevention and control mechanism of the State Council, Mi Feng, spokesman of the National Health Commission, introduced: At present, the overall epidemic situation in the country has entered a low epidemic level, the epidemic situation in various places has maintained a steady decline trend, and there are no new variants circulating abroad in China, and the current round of the epidemic is nearing the end.
On the same day, the WHO issued a statement saying that the pandemic still constitutes a "Public Health Emergency of International Concern (PHEIC)" and that it remains "a dangerous infectious disease that can cause significant damage to personal health and medical systems"[1].
Source: References[1]
Li Feng (pseudonym), vice president of a tertiary hospital in East China, said that the hospital has recently returned to the pre-epidemic reception state, "Of the 40 clinical departments, about 1/10 is left to be responsible for the treatment of new crown-related diseases, and other departments have resumed ordinary operations."
But he also mentioned that in the intensive care ward of the hospital, the bed utilization rate of new crown-related critical patients is about 50%, and "the focus of the work of several mainstream departments (such as respiratory, infection, severe disease, etc.) is still on the diagnosis and treatment of the new crown."
How to define "low prevalence level"?
According to the China Disease Control [2] report: the current round of the epidemic in the mainland reached a peak in late December 2022, and has continued to decline since then, with the trend of all provinces basically similar, urban and rural areas basically synchronizing, and the number of outpatient (emergency) departments, the number of critically ill people in hospital, and the number of deaths in hospitals all showing a downward trend. By the end of January, the overall epidemic situation in the country had been reduced to a low level, the pressure of medical treatment was further eased, the epidemic did not rebound significantly during the Spring Festival holiday, and no new variants were found during the entire epidemic process, and the current round of the epidemic in the mainland was nearing its end.
Source: References[2]
From the perspective of several definitions of epidemiology, disease outbreaks usually follow the emergence of epidemics, and can be divided into endemics, large-scale regional epidemics and pandemics according to the degree of epidemic.
Endemic endemic is often confined to villages or towns, and is relatively stable and easy to control; Large-scale regional epidemics spread over a large geographical area, such as the Ebola virus circulating in West Africa in 2014~2016; The pandemic is the progression of a large-scale regional epidemic that has global reach, such as the 1918 Spanish flu pandemic and the 2009 H1N1 flu [3].
Source: References[3]
There is no agreed definition of "low prevalence level".
Lu Mengji, a German virologist of Chinese descent and professor at the Institute of Virology at the University of Essen School of Medicine, said, "From a quantitative point of view, it is possible to detect the population data of infection, age distribution, disease situation, geographical distribution, etc., so as to statistically count the infection data of the population with a specific geographical distribution, and obtain the curve distribution under different horizontal and vertical coordinates, so as to study and judge the epidemic."
However, the ideal data model will be limited by the sampling bias of the detection population, as well as the monitoring dimension and cycle of the sample. "In Germany, different states and counties will collect the infection data of the population in the region to obtain the data curve, but the infection curve is often not simply rising and falling."
From the perspective of the characteristics of the new crown epidemic, Zhang Wenhong and many other experts agree that the new crown will gradually change from a pandemic to an endemic and seasonal epidemic.
Academician Gao Fu also said that to end the new crown pandemic, there are two words that are key, one is tolerance, the other is resilience, "When human beings can tolerate the existence of the virus, have a certain degree of resilience, can live normally, and coexist with it, the pandemic can be declared over." When the new crown is only epidemic in some areas, it becomes an endemic epidemic. By summer or autumn, it is possible that WHO will declare the pandemic over. But this does not mean that the death toll from the new crown will be as low as that of the flu, because its infection base is too large. As for when it will be the same as the flu, it is difficult to predict."
As countries gradually loosen their coronavirus controls, the need to continue the coronavirus emergency has become a hotly debated issue.
It is reported that Biden plans to announce the lifting of the US public health emergency on May 11 this year, but at the same time stressed that the United States needs to gradually transition from the state of emergency to normal, rather than suddenly lifting. Asked why the decision was made, a White House spokesman said that from 2020 to 2022, the new crown was the third leading cause of death in the United States, and now the new crown is outside the fifth place.
Zeng Guang, former chief expert in epidemiology at the Chinese Center for Disease Control and Prevention, said: "Combined with China's own reality, 80~90% of the population has obtained natural immunity after natural infection, and the domestic vaccination rate has reached a level of more than 90%, and China's immune barrier has been basically established. Although the epidemic situation is safe in the short term and the storm has passed, there are still many variables in the medium and long term."
Second round peak ≠ secondary infection
Before the holiday, the second round of peaks is a hot topic recently. As mentioned in the previous article [4], the passing of a peak does not mean the end of the epidemic, and the virus will return at a specific time. In Japan, for example, Japan has seen at least 8 waves of coronavirus peaks since the onset of the coronavirus.
Wu Zunyou, chief expert in epidemiology at the Chinese Center for Disease Control and Prevention, once predicted a model of "twists and turns": from mid-December to mid-January 2023, the first wave of the epidemic mainly rose in large and medium-sized cities across the country. From late January to mid-February, pre-Spring Festival mobility caused a second wave of the epidemic to rise. From late February to mid-March, the return to work and migrant workers after the Spring Festival triggered a third wave of the epidemic.
It is worth mentioning that the "second round of peaks" mentioned recently is not the "secondary infection" that everyone is worried about.
As mentioned in previous articles [5], the current dominant strains in the mainland are still BF.7 and BA5.2, and the people infected in the first round of infection are unlikely to be infected twice within 3~6 months. However, the XBB strain circulating in the United States has shown a strong immune evasion ability, and the article published in Lancet pointed out [6], the S:S486P mutation obtained by XBB.1.5 enhances its affinity for ACE2 receptors, thereby showing greater transmissibility, infectiousness and immune evasion, and predicts that XBB.1.5 will spread rapidly worldwide in the near future.
Although the XBB variant has not yet caused widespread transmission in the mainland [7], the possibility of secondary infection caused by XBB in the mainland still exists given its strong immune evasion ability. In addition to the XBB variant, the new strain CH.1.1 is gradually occupying the public eye. As of January 30, a total of 24 cases of CH.1.1 have been detected in mainland China.
In addition, referring to Singapore's experience [8], in the face of XBB, which has a strong immune evasion ability, the vast majority of reinfected people were last infected with the variant before Omicron, not Omicron. Although people who were last infected with Omicron may also be reinfected with XBB, it is also more likely to be more than six months after the last infection. If the patient was last infected with Omicron within three months, the probability of reinfection with XBB is low.
In the short term, it is unlikely that secondary infections on the mainland from new variants will cause a second wave peak.
Source: References[9]
For when the second wave of peaks will come, Professor Lu Mengji, a German Chinese virologist and professor of the Institute of Virology at the University of Essen School of Medicine, believes that "at present, the peak of large-scale infections in China is very fast, and the immunity barrier of the overall population is relatively low. As population immunity declines, the risk of infection increases in the population, and virus evolution is not a predictable process, so the possibility of new strains becoming popular cannot be ruled out."
Doctor: There are still more than 50% of COVID patients in the ICU
The perspective is pulled to the clinical dimension, and the pressure of medical treatment is further relieved after the peak. Liu Minli (pseudonym), a doctor working in the central region, said that his hospital's current focus is to cope with the second-class review, and everything else has returned to normal, "The hospital no longer arranges training for the diagnosis and treatment of the new crown, and the focus of surgery is on surgery after the peak, and internal medicine has also returned to the past."
Li Feng (pseudonym), vice president of a third-class hospital in East China, also said that his hospital has now returned to the pre-epidemic reception state, "The doctors gathered by the respiratory treatment team have now returned to their original departments."
At present, in the intensive care ward of Li Feng's hospital, the bed utilization rate of new crown-related severe patients has dropped to less than 60%. Looking back at this anti-epidemic process, Li Feng believes that the hospital has accumulated a lot of experience in severe treatment, "From the overall data, our response to the epidemic at the end of 2022 is still relatively scientific, reasonable and effective, but in the face of possible future epidemic changes, we still need to be cautious about precautionary rewards."
Source: Visual China
According to the data of Singapore and other countries [9] and the actual situation in the mainland [5], the possibility of large-scale infection within 3~6 months is not large. But after 3~6 months of infection in this round of the epidemic, as the immunity obtained by the population from infection with the new crown gradually declines, a new peak of infection may be formed.
From the perspective of public health, Professor Lu Mengji believes that "in an emergency and dynamic public health emergency, monitoring severity indicators such as severe disease rate and hospitalization rate, and paying attention to sudden indicators such as strain sequencing, can provide guidance for the research and judgment of the epidemic." However, he also stressed the need to continue to pay attention to the vaccination status of key groups, "We cannot judge the status of the epidemic from big data alone, because for individuals, the risk factors that need to be carried are far greater than simple data, so we should continue to improve the personal protection awareness of individuals."
An article published in The Lancet [10] points to some of the problems exposed in China during this round of infections, such as insufficient vaccination coverage among key populations. By the end of November, only 69% of people over 60 years of age and 40% of people over 80 years of age were fully vaccinated (2 doses plus 1 booster dose). In addition, bivalent mRNA vaccines against the latest variants are still in development, and current domestic vaccines have limited efficacy against XBB variants.
Wang Quanyi, deputy director of the Beijing Municipal Center for Disease Control and Prevention, introduced on January 31 that Beijing will soon carry out a population serum antibody survey to understand nucleic acid and antigen testing, onset and prognosis, vaccination status and other information. Beijing has established temporary population immunity protection, and the risk of recent epidemics is small, and the elderly over 80 years old can be vaccinated in time during this "window period".
From the perspective of clinical management, Li Feng, vice president in charge of hospital drug and equipment procurement, believes that in the precious window period of 3~6 months, how to prepare materials is also an important proposition in the near future. Because of the construction of the gridded medical alliance, the hospitals in his province, city, county and township were linked, packaged for expansion, wards, ventilators and other equipment were doubled according to the number of intensive care beds, and the procurement of new crown drugs was prepared at the same time.
Li Feng said, "If the public health angle is more 'prevention', then the clinical angle must be more 'treatment'. The past experience in intensive care, the preparation of materials during the window period, and the expansion of ICU are all beneficial to our response to the recurrence of the epidemic that may come."
Planned by Carollero | Executive Producer: Gyouza
Thanks to Yusi Wang for contributing to this article
Source: Visual China
Resources:
[1] World health organization. Statement on the fourteenth meeting of the International Health Regulations (2005) Emergency Committee regarding the coronavirus disease (COVID-19) pandemic. 2023 [cited 2023 Jan 31]; Available from: https://www.who.int/news/item/30-01-2023-statement-on-the-fourteenth-meeting-of-the-international-health-regulations-(2005)-emergency-committee-regarding-the-coronavirus-disease-(covid-19)-pandemic.
[2] China CDC, COVID-19 Clinical and Surveillance Data — December 9, 2022 to January 23, 2023, China. China CDC Weekly, 2023.
[3]. Grennan, D., What Is a Pandemic? JAMA, 2019. 321(9): p. 910.
[4]. Lilac Garden. When will the peak of the epidemic arrive? The forecast for many places is concentrated in the next 1~2 months. 2022.
[5]. Lilac Garden. Where the XBB peak has passed, is the population with a high rate of secondary infection? . Jan 14, 2023.
[6]. Keiya Uriu, J.I., Jiri Zahradnik, Shigeru Fujita, Yusuke Kosugi, Gideon Schreiber, Enhanced transmissibility, infectivity, and immune resistance of the SARS-CoV-2 omicron XBB.1.5 variant. The Lancet Infectious Diseases, 2023.
[7.]CDC. COVID Data Tracker Weekly Review. 2023 Jan 6, 2023 [cited 2023 Jan 11]; Available from: https://www.cdc.gov/coronavirus/2019-ncov/covid-data/covidview/index.html.
[8.]Singapore Ministry of Health. Corrections regarding XBB wave in Singapore - False statements about COVID-19 situation in Singapore. 2022 Oct 14, 2022 [cited 2023 Jan 11]; Available from: https://www.gov.sg/article/factually141022-a.
[9] Singapore Ministry of Health. UPDATE ON COVID-19 SITUATION AND MEASURES TO PROTECT HEALTHCARE CAPACITY. 2022 Oct 15, 2022 [cited 2023 Jan 12]; Available from: https://www.moh.gov.sg/news-highlights/details/update-on-covid-19-situation-and-measures-to-protect-healthcare-capacity.
[10] The Lancet., The COVID-19 pandemic in 2023: far from over. Lancet, 2023. 401(10371): p. 79.