The author of this article: Zhang Zuofeng
im width=”600″>
Professor Yu Shunzhang is a well-known epidemiologist in China and my postgraduate tutor.
During the SARS epidemic in 2003, Deputy Head of Shanghai Expert Advisory Group, Professor of School of Public Health, Shanghai Medical University Yu Shunzhang and Weng Xinhua, director of the Department of Infectious Diseases of Huashan Hospital, suggested that Shanghai should cite stricter diagnostic criteria that are different from national standards, including the exposure history of other provinces and cities into the diagnostic criteria.
author’s drawing
Omicron BA.2 has the following main characteristics: it is more infectious than BA.1; after infection with BA.2, the hospitalization and severe rates are similar to BA.1; Causes the protection of the vaccine to decrease, but the reinfection rate of people who have been infected with BA.1 is very low at present; the main symptoms after BA.2 infection are similar to colds, mainly runny nose, headache, fatigue, sneezing and sore throat ;BA.2 basically does not attack the lungs, and is less likely to cause severe illness and death.
According to the principle, through the static management of the population, the During the incubation period of 3 to 4, the infection should be properly controlled, and the epidemic curve should shift back to the sudden peak.
But why is the daily number of new infections in Shanghai maintained at around 20,000? We guess that the irregular operation in the group nucleic acid sampling process and exposure may be important reasons.
The risk may arise from the sampling process itself not being Normative, did not pay attention to the disinfection measures in each sampling, such as changing gloves, etc. The social distance between people and people during sampling was too small, and when sampling If it is positive, the latter person may be infected.
More importantly, the organizer responsible for maintaining order Or volunteers may have a higher infection rate due to their extensive contact surface and have not received strict disinfection training, thus becoming a potential source of infection.
Secondly, it was the frenzied purchases before the blockade. There was no obvious social distancing, and few people wore masks. Coupled with multiple rounds of nucleic acid sampling, it became an accelerator for the spread of infection.However, the above reasons can only explain the continued increase in the incidence during the incubation period after static management, and cannot explain Continued increase observed so far.
What is different from Shenzhen is that although Shenzhen has been closed and controlled, social services are still as usual, and food and drug supply channels are unobstructed, thus effectively avoiding It eliminates the possibility of frantic purchases and mail order, and reduces the risk of transmission.
In Shanghai, because the food and drug supply chain is basically unconnected, residents order online through the neighborhood committee, volunteers, and Delivery by riders, these groups of people have not received personal protection training, which may lead to an increased risk of infection and become the main source of infection for further outbreaks.
Why is the epidemic in the suburbs of Shanghai lighter than in the urban areas? Differences in population density, low population density can reduce exposure and transmission coefficient in population nucleic acid sampling.
In summary, the reason for the high level of the new crown epidemic in Shanghai is mainly the In terms of infectious preventive measures, timely and targeted improvements have not been made under the premise of dynamic clearing.
On March 27th, the first day of Pudong’s closure, I proposed to Shanghai Four suggestions for the control of the new crown epidemic: including self-nucleic acid sampling or self-antigen assay (which has been carried out in Shanghai in the future), self-isolation at home if conditions permit, enhanced vaccination of elderly at risk groups, and early treatment of patients.
These suggestions are based on the premise of dynamic clearing, according to the new characteristics of virus mutation, to prevent adjustment of measures. If there are improvements in preventive measures against the characteristics of the virus, the Shanghai epidemic will ease.
In addition, urgent vaccination of the elderly and high-risk groups is recommended; self-sampling and antigen testing are allowed ; And in the early stage, the antigen-positive people were required to be sampled at home by their family members, and the deep throat saliva sample collection bottle was obtained to re-examine the nucleic acid and confirmed the diagnosis. This approach can avoid cross-infection caused by crowd gathering.
The fifth round of epidemic in Hong Kong has accumulated 1.18 million cases of new crown infection, it is estimated that from February 26 to March The 180,000 infected people who were confirmed by the antigen self-test on the 6th implemented home self-isolation, at least not exacerbating the epidemic. Self-isolation at home for those who are infected has also reduced the possibility of cross-infection in the cabins, so as to reduce the probability of producing new variants of the virus.
Estimated case fatality rate
Shanghai should not have the same high fatality rate as Hong Kong. According to Hong Kong data, 8735 deaths 92% had long-term underlying diseases (deaths with Covid-19), only 8% ( 699)classified as Covid-19 deaths(deaths from Covid-19).
At the same time, the fatality rate of the new crown in Hong Kong is obviously overestimated. Its denominator should include a large number of unreported potentially infected people, and if included, the new crown case fatality rate may be close to 0.1%.
Hong Kong data also show that the vaccination rate of people over 80 years old is less than 20%, and a high proportion of of deaths are in people over the age of 80. This also underscores the need to urgently strengthen the vaccination of high-risk groups in the elderly population to reduce the case fatality rate.
More than 70% of deaths were unvaccinated (including those who received one shot but less than 14 days old), 14% received one shot, 11% received two shots, 1 % received three shots of the vaccine. (Source: Hong Kong Government)
Under the big goal of dynamic clearing, for no For non-fatal infectious diseases with relatively high symptoms or mild symptoms, the hospitalization rate, severe illness rate, and case fatality rate (number of deaths/number of sick people) can be considered as indicators of dynamic clearing and control, rather than the number of cases and the number of cases. morbidity.
According to the current situation: Shanghai Omicron BA.2 belongs to this example. At present, the case fatality rate of the Omicron BA.2 variant is close to 0.1% in France and other places, which is close to the case fatality rate of the local influenza.
Among the more than 500,000 infections in Shanghai, there are very few severe and fatal cases, and there is currently no direct The cases of death from new coronary pneumonia also reflect the epidemic characteristics of BA.2.
According to the laws of epidemiology, I died of the new crown infection in Shanghai rate is predicted. My assumptions are: an average of two weeks from the onset of severe cases to death, the fatality rate of this virus is similar to that of the flu, and the accuracy of the data reported in Shanghai is assumed to be high (see figure below).
p>
The results found that as of April 10, Shanghai had reported 138 deaths from new coronary infection (zero deaths directly from new coronary pneumonia), and I predicted the corresponding expected deaths The number is 202 cases. Although the actual number of deaths is currently lower than I predicted, I estimate that there may be a lag in reporting and the possibility of underreporting.
At the same time I predict a total of 370 deaths by May 1 and a total of 370 deaths by May 8 The number is 505 cases. If my prediction is accurate, then it may be estimated based on the data: the case fatality rate of the new coronavirus BA.2 is comparable to the average case fatality rate of the local influenza, and it can be considered that the new crown infection has been transformed into an endemic disease. In this case, it is recommended to consider to adjust the prevention and control measures of class B infection of novel coronavirus pneumonia to class C prevention and control measures of infectious disease C.
Under the premise of dynamic clearing, we can reduce social closure, ease hospital runs, and strengthen vaccines Vaccinations and personal protection, reduce deaths, and effectively control the new crown epidemic in Shanghai.
This article was first published on Prof. Zhang Zuofeng’s personal beauty editor account, authorized to publish by Lilac Garden. Source of title map:Visual China｜Planning:gyouza
Conflict of interest statement:< /span>
1. This article was completed by the author in his spare time and has not received any financial support.
2. The vaccines and therapeutic drugs introduced in this article are based on three conditions, one is supported by large-scale phase III clinical trial data, and the other is in terms of prevention and treatment. It is the most effective, and thirdly, it is easier to obtain in China than other foreign drugs.
3. The author has no investment in pharmaceutical companies.
More related content review
Professor Zhang Zuofeng: Reflections and Suggestions on the Current New Crown Epidemic in Shanghai
Wang Liming: Comments on Professor Zhang Zuofeng’s 4 Comments on the Prevention and Control of the Epidemic in Shanghai
6 lessons from the fifth wave of the epidemic in Hong Kong: Journal reviews
Experts : Shanghai added 23,000 in a single day. Is home isolation feasible for asymptomatic?