Tuesday, May 12, 2020

Chinese epidemiologist : Virus content in the air is higher when taking off clothes and other issues

Source: CCTV News , Reproduced on China News Network
Ref : http://www.chinanews.com/gn/2020/05-12/9181639.shtml
Translation, editing : Gan Yung Chyan
                               / KUCINTA SETIA

Image : A campaign in Shulan to prevent and control the spread of SARS-CoV-2.



News 1 + 1 丨 How to treat newly-increased local cases? How to implement normalized prevention and control? Bai Yansong interviews Wu Zunyou, an epidemiologist at the China Center for Disease Control.

Since 7 May 2020, Shulan, Jilin Province has added 15 locally confirmed covid cases. On 10 May 2020, Shenyang, Liaoning Province has added a new local confirmed case. The case arrived in Shenyang from Jilin by high-speed train on 5 May. Since 9 May 2020, Wuhan, Hubei Province has newly confirmed 6 cases, all from the same community. How to treat these new local cases? How to implement normalized prevention and control of the epidemic situation? "News 1 + 1" Bai Yansong, interviews Wu Zunyou, chief expert in epidemiology at the China Center for Disease Control and Prevention, who interprets it for you.

Covid is far more complicated than SARS; sporadic case reports are expected

Wu Zunyou: This situation is expected. On  "News 1 + 1" of 30 January, I told everyone that the tailing would be quite long, and now it has been confirmed that the tailing is quite long. When we see daily sporadic case reports, especially reports of positive cases, we know that sporadic occurrences will occur. Regarding "zero cases", everyone has a different expectation. During the SARS epidemic in 2003, when there were zero cases and no new reported cases after the double clearing, many people remembered the history or experience of SARS In my mind, when covid cases appear "zero", we also hope the disease to be like SARS. Covid is far more complicated than SARS, and our knowledge about it is still very limited. From the perspective of its mode of transmission, difficulty in prevention and control, and clinical manifestations, it is much more complicated and difficult than SARS. Its understanding has been further improved.


Jilin Shulan's first diagnosed laundry worker is not necessarily the source

Wu Zunyou: After the cluster epidemic occurred, the epidemiological investigation tried to find the source, and it was indeed difficult to find the source. Yesterday, the Chinese Center for Disease Control also sent professionals to Shulan to assist in the investigation. From the current situation, it is difficult to judge whether the first patient diagnosed is the source patient. This patient is a laundry worker. At present, there is a speculation that she may be the source of this cluster epidemic, but there is another possibility that there is still a real source that has not been discovered, which may be determined in due time. On the main source of transmission, these require more epidemiological investigations, or require biological means to analyze and speculate. There is also a possibility that the incubation period of some patients may be longer than that of this laundry worker. An earlier patient may have transmitted it to this laundry worker, and the latent period of this laundry worker is relatively short, which may occur in two or three days, and the real source. The patient may become ill seven or eight days after the infection, and the incubation period is infectious. If this is the case, it is very difficult to judge who transmitted the virus to whom.

Is the diagnosed patient of Jilin Shulan related to the patient entering Russia?

Wu Zunyou: What needs to be done right now is to analyze the genetic sequence of the viruses of this group of patients with aggregated cases and the viruses of patients entering from Russia to see their homology. If the homology is very consistent, it can be presumed It is related to the case of Russian entry cases, and it is difficult to determine the specific relationship.

Jilin Shulan confirmed that the laundry worker was infected by clothes. Is it possible?

Wu Zunyou: A few days ago, there was a research report about the virus content in the air. The researchers sampled the air in hospital wards, the air in the semi-contaminated area where doctors changed their isolation suits, and the air in the clean area. In the space where the isolation suit is replaced, the virus content in the air is higher. That is to say, if the medical staff is in the ward, his clothes may be infected with the virus. During the process of taking off, the virus content in the air is higher. Does this suggest that there are similar situations in Shulan's cluster cases? These also provide a new idea for our analysis.

Bai Yansong: In the case in Shulan concerning the laundry worker of the Public Security Bureau, the Public Security Bureau was involved in picking up people (Russian immigrants) from 8 April to 30 April. Could the laundry worker have been infected during the process of washing the Public Security forces' uniform?

Wu Zunyou: There is such a possibility.

Tips for confirmed cases from Jilin to Shenyang: take protective measures in traffic-tight environment

Wu Zunyou: We are likely to encounter infected patients or patients in the incubation period during our travels. It also reminds us that we must adhere to protective measures in a traffic-tight environment. For such a case, he will have many infected people along the way, and it also reminds us that it is very difficult to investigate the close contacts completely. It it is also very difficult because there may be missing close contacts. If he is infected or sick, he may cause a new mass epidemic.

Normalized epidemic prevention does not mean that the epidemic is gone. Daily protective measures must be done

Wu Zunyou: Everyone may have a different understanding towards normalized epidemic prevention. Is it possible to completely return to the living conditions before the covid epidemic occurred? This is not what it actually means. The so-called normalized epidemic prevention means that we can basically resume normal life and work when we take protective measures. In a normalized environment, we still need to follow the requirements of the prevention and control guidelines in the places where people gather and in closed places. It is still necessary to take protective measures, especially when we are traveling, we must pay attention to protection.

On the first confirmed case in Sanming, Wuhan Dongxihu, why is it so long from March to May?

Bai Yansong: The day before yesterday, Wuhan announced a confirmed case in the community. The initial judgment was that the cause was a previous community infection. However, this case had symptoms in March, and then the symptoms disappeared. Until now, the diagnosis has been confirmed. How to analyze his history of onset for more than two months?

Wu Zunyou: We have also noticed that this patient, in fact, has more than one such case in Wuhan, and some may have a course of 30 days, 40 days, or even 50 days. For the rehabilitation of patients with covid, it mainly depends on the patient's immunity and resistance. If the patient's immunity is strong, he can remove the virus in a short time. If the patient's resistance is weak, he cannot remove the virus. The virus may stay in the body for a long time. This shows that when people are old and have low immunity, the course of the disease may be very long, and there may be recurrence. This is a major difference between covid and SARS, and other diseases. According to the analysis of the disease spectrum of different age groups, the younger people, especially children, have a higher proportion of asymptomatic infections, and the younger people have milder symptoms, all of which point to the symptoms presented by the patient and the speed of recovery. These issues are related to immunity.

Why are the 6 new cases in Wuhan from the same community?

Wu Zunyou: As long as there is no real "zero" case in the community, or there are still positive cases in the community, all have risks of infection. A considerable number of people who test positive and have asymptomatic infections have very mild symptoms that he can't feel himself. They are still infectious. After he infects the patient, the infected person may or may not have symptoms. With or without symptoms, he still has the risk of spreading to other people, and the community should still be vigilant and strengthen prevention.

Nucleic acid detection is mainly aimed at key regions and key populations

Netizen: On 10 May, five new confirmed cases in Wuhan came from the Changqing Street community (Sanming). Does this mean and do we need to perform nucleic acid testing on the entire population to screen for asymptomatic infections?

Wu Zunyou: Should large-scale screening nucleic acid tests be done by everyone? In fact, it is not necessary, mainly in key areas and key people. As the netizen said just now, large-scale screening is still necessary. In those communities without cases, there is no need for everyone to do screening, People from key posts, key populations, and key communities should come forward for large-scale screening.

Wuhan's super-long-onset confirmed cases suggest the cunning nature of  SARS-CoV-2. It is currently impossible to determine the way it coexists with humans

Wu Zunyou : Our knowledge of  the virus SARS-CoV-2 is still very limited. This limitation prevents us from researching or determining the way it will coexist with humans in the future. At present, it will not disappear as quickly as SARS. It is uncertain how long it will coexist with humans or coexist with us in a form of epidemic. On the other hand, its clinical manifestations are also very special. The case of the old man you just mentioned also shows that clinical manifestations of the virus are very special. These are our understanding of SARS-CoV-2.

Sporadic cases will no longer cause a certain scale of epidemics

Wu Zunyou: I don't think there will be a small peak. After more than three months of hard work, we have succeeded in controlling covid, and we have achieved at least a lot of experience. These experiences will not cause sporadic cases to cause a certain scale of epidemic. Because of our surveillance system, as long as the cases are found, timely investigation and timely tracking are done, the epidemic can be extinguished quickly, and there should be no small epidemic peaks.

Netizen: The weather is getting hotter and hotter. Many people can’t wear the masks. What should we do?

Wu Zunyou: The question of masks is indeed a very complicated and scientific issue. For big open areas at home, in the family, you no need to wear masks. In public places, especially in closed environments, even if it is very hot, it is still necessary to wear a mask. There is no indication that after the weather is hot, there will be no transmission of covid. Regarding such data, the weather is not hot enough that we cannot wear masks. We still have to overcome some difficulties and insist on wearing masks. Before there is no definite evidence, we cannot take off the mask completely.

Will the inaccurate temperature measuring gun affect the prevention and control effect?

Wu Zunyou: We are not the only ones who rely on body temperature measurement and symptom monitoring. The patient's performance may be feverish, some do not have a fever at the beginning, and they may have coughs and fatigue. The monitoring of these symptoms is also very important.

Non-symptomatic patients with covid are infectious when they have no clinical symptoms.

Wu Zunyou: I would like to remind you that covid is particularly infectious, especially when the patient has not yet developed clinical symptoms. Covid is already infectious. The discovery of the virus detoxification rules for infected people shows that the clinical symptoms appear in patients and within the first one or two days they will be contagious. For everyone, to prevent covid, we still have to persevere, and in places where people gather, we still have to insist on wearing masks. These protective measures cannot be given up.

StayGate's Note
Covid is officially known as "novel coronavirus pneumonia" in the People's Republic of China. The translation uses "covid" to facilitate international understanding on the disease subject.

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