Writers : Zhang Ruoting, He Liping
Ref : http://news.sciencenet.cn/htmlnews/2020/4/438780.shtm
Translation, editing : Gan Yung Chyan
/ KUCINTA SETIA
Image courtesy : Shutterstock
New research by the Zhejiang University School of Medicine and other teams on the time and load of viruses in different tissue samples of patients diagnosed with SARS-CoV-2 (covi, in short) shows that the duration of the virus in feces is higher than that in the respiratory and serum samples. It is much longer and the peak viral load in feces appears later.
On 21 April 2020, the international top medical journal BMJ ("British Medical Journal") published a research article "Viral load dynamics and disease severity in patients infected with SARS-CoV-2 in Zhejiang province, China, January-March 2020 : retrospective cohort study"(https://www.bmj.com/content/369/bmj.m1443), the research team includes a number of medical professional teams in Zhejiang, including the Clinical Laboratory Center of the First Affiliated Hospital of Zhejiang University School of Medicine, Cooperative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Bone Marrow Transplantation Center, Pharmacy, and Respiratory Disease And other departments; Institute of Laboratory Medicine, Zhejiang University; Zhejiang Pancreatic Disease Research and Innovation Center, etc.
Corresponding author of this article is Liang Tingbo, professor of Zhejiang University School of Medicine and recipient of the National Natural Science Foundation Outstanding Youth Fund.
At present, the relationship between the viral load changes of covi in different tissue samples such as lower respiratory tract, feces, serum, and urine and the severity of the disease is still unknown, and this information is crucial for the development of disease control strategies and clinical treatment.
Through a retrospective cohort study, the authors systematically evaluated 3497 samples collected from 96 inpatients of the First Affiliated Hospital of Zhejiang University School of Medicine infected with covi from 19 January 2020 to 20 March 2020, and analyzed the time variation of viral load and the correlation between viral load in different sample types and disease severity.
The research team found that the duration of SARS-CoV-2 in fecal samples was significantly longer than that in respiratory and serum samples, which highlighted the risk of viral fecal transmission, indicating the need to strengthen the management of fecal samples in the prevention and control of new crown outbreaks.
In addition, it is worth noting that in critically ill patients, the virus persists in the respiratory system and feces for a longer time and greater load, and the time to reach the peak may be later than known.
Viruses in feces last a long time, with the highest viral load in respiratory samples.
The study sample included 22 mild patients and 74 severe patients. The research team collected their epidemiological, clinical and laboratory characteristics, treatment and outcome data through the patients' electronic medical records.
The results of the study showed that virus RNA was detected in the feces of 55 patients (59%) and in the serum of 39 patients (41%), and there was no difference in the detection rate of fecal virus between mild and severe patients.
It is worth noting that the detection rate of covi in respiratory samples of diagnosed patients gradually decreased from 95% in the first week of symptom onset to 54% in the fourth week, and subsequent respiratory samples were negative; feces and serum The positive rate of the sample gradually increased from the first week, and then began to decrease from the third week.
Although the detection rate of viral RNA in the urine of SARS (Severe Acute Respiratory Syndrome) patients was as high as 50%, in this study, the researchers found covi in only the urine samples of one critically ill patient RNA.
The detection rate of viral RNA in serum is also significantly different from SARS. Some previous studies have found that as many as 79% of serum samples contain SARS virus RNA in the first week of symptoms, which is the proportion in the second week About 50%. However, in this study, the detection rate of covi in the patient's serum was only 41%.
The number of positive virus detected in the respiratory tract, feces, serum, urine samples of patients with mild or severe new crown diagnosed at different stages after the onset of symptoms. The figures in the table are the number of patients with covi positive in a tissue / the total number of patients.
The researchers found that the duration of the virus in the stool of the diagnosed patient (22 days, quartile range 17-31 days) was significantly longer than that of the respiratory system (18 days, 13-29 days) and serum samples (16 days, 11-21 days).
In addition, the duration of the virus in respiratory samples of patients with severe diseases is significantly longer than that of patients with mild diseases; there is no significant difference in the viral load in feces and serum samples of mild and severe patients.
There are significant differences in viral load among different tissues. Among the samples studied, respiratory samples had the highest viral loads, followed by stool samples, and serum samples had the lowest viral loads.
Through local weighted regression analysis, the researchers found that in the mild group, the viral load in the patient's respiratory tract sample peaked at the beginning of the second week of the disease; in the severe group, the viral load in the patient's respiratory tract sample was The third and fourth weeks continue to rise.
Similar to the trend of viral load in respiratory samples of critically ill patients, in the third and fourth weeks after the onset of the disease, the viral load of the patient's stool samples was the highest.
Since the onset of symptoms, changes in viral load in respiratory samples of mild and severe patients and all stool samples, purple represents respiratory samples of severe patients, yellow represents respiratory samples of mild patients, and pink represents stool samples of all patients
Viruses in lower respiratory tract samples last longer than upper respiratory tract, and peaks appear later
The researchers found that the researchers found that the type and duration of antiviral treatment had no overall effect on the duration and viral load of the virus.
In critically ill patients, the virus duration of patients receiving continuous glucocorticoid therapy for more than 10 days is much longer than that of patients with continuous treatment for less than 10 days. influences.
At present, the therapeutic effect of glucocorticoids and antiviral drugs on covid patients is unclear. The researchers emphasized that since the types and doses of antiviral drugs and glucocorticoids were not analyzed, the effects of antiviral drugs and glucocorticoids cannot currently be evaluated.
The authors said that in the next step, the effectiveness of antiviral drugs and glucocorticoids needs to be verified by more multi-centre randomized studies.
After stratifying the critically ill patients, the researchers found that the duration of the virus in males was significantly longer than that in females, and that in patients over 60 years old and male patients was longer.
In addition to the differences in the immune status of men and women, the causes of gender differences in virus duration may also be related to the differences in hormone levels. Part of the reason that the virus lasts longer in elderly patients is due to immune aging, and another reason is that the covi "receptor" angiotensin-converting enzyme 2 is higher in the alveoli of the elderly.
A previous study found that the peak load of covi in patients' upper respiratory tract samples appeared in the early stages of the disease. However, the researchers found that in the lower respiratory tract samples, the "viral shedding" of the new coronavirus lasted longer, and the peak appeared late, and the peak detoxification appeared only about two weeks after the onset of symptoms.
The researchers believe that these findings are important for effective control and prevention of the new crown epidemic, because this indicates that the entire disease process of covid patients must be strictly managed.
Based on the research results, the authors believe that the role of fecal excretion in the transmission of covid cannot be ignored. However, in the prevention and control of the covid epidemic, the feasibility of large-scale testing of stool samples also requires a comprehensive and careful evaluation.
Ref : http://news.sciencenet.cn/htmlnews/2020/4/438780.shtm
Translation, editing : Gan Yung Chyan
/ KUCINTA SETIA
Image courtesy : Shutterstock
New research by the Zhejiang University School of Medicine and other teams on the time and load of viruses in different tissue samples of patients diagnosed with SARS-CoV-2 (covi, in short) shows that the duration of the virus in feces is higher than that in the respiratory and serum samples. It is much longer and the peak viral load in feces appears later.
On 21 April 2020, the international top medical journal BMJ ("British Medical Journal") published a research article "Viral load dynamics and disease severity in patients infected with SARS-CoV-2 in Zhejiang province, China, January-March 2020 : retrospective cohort study"(https://www.bmj.com/content/369/bmj.m1443), the research team includes a number of medical professional teams in Zhejiang, including the Clinical Laboratory Center of the First Affiliated Hospital of Zhejiang University School of Medicine, Cooperative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Bone Marrow Transplantation Center, Pharmacy, and Respiratory Disease And other departments; Institute of Laboratory Medicine, Zhejiang University; Zhejiang Pancreatic Disease Research and Innovation Center, etc.
Corresponding author of this article is Liang Tingbo, professor of Zhejiang University School of Medicine and recipient of the National Natural Science Foundation Outstanding Youth Fund.
At present, the relationship between the viral load changes of covi in different tissue samples such as lower respiratory tract, feces, serum, and urine and the severity of the disease is still unknown, and this information is crucial for the development of disease control strategies and clinical treatment.
Through a retrospective cohort study, the authors systematically evaluated 3497 samples collected from 96 inpatients of the First Affiliated Hospital of Zhejiang University School of Medicine infected with covi from 19 January 2020 to 20 March 2020, and analyzed the time variation of viral load and the correlation between viral load in different sample types and disease severity.
The research team found that the duration of SARS-CoV-2 in fecal samples was significantly longer than that in respiratory and serum samples, which highlighted the risk of viral fecal transmission, indicating the need to strengthen the management of fecal samples in the prevention and control of new crown outbreaks.
In addition, it is worth noting that in critically ill patients, the virus persists in the respiratory system and feces for a longer time and greater load, and the time to reach the peak may be later than known.
Viruses in feces last a long time, with the highest viral load in respiratory samples.
The study sample included 22 mild patients and 74 severe patients. The research team collected their epidemiological, clinical and laboratory characteristics, treatment and outcome data through the patients' electronic medical records.
The results of the study showed that virus RNA was detected in the feces of 55 patients (59%) and in the serum of 39 patients (41%), and there was no difference in the detection rate of fecal virus between mild and severe patients.
It is worth noting that the detection rate of covi in respiratory samples of diagnosed patients gradually decreased from 95% in the first week of symptom onset to 54% in the fourth week, and subsequent respiratory samples were negative; feces and serum The positive rate of the sample gradually increased from the first week, and then began to decrease from the third week.
Although the detection rate of viral RNA in the urine of SARS (Severe Acute Respiratory Syndrome) patients was as high as 50%, in this study, the researchers found covi in only the urine samples of one critically ill patient RNA.
The detection rate of viral RNA in serum is also significantly different from SARS. Some previous studies have found that as many as 79% of serum samples contain SARS virus RNA in the first week of symptoms, which is the proportion in the second week About 50%. However, in this study, the detection rate of covi in the patient's serum was only 41%.
The number of positive virus detected in the respiratory tract, feces, serum, urine samples of patients with mild or severe new crown diagnosed at different stages after the onset of symptoms. The figures in the table are the number of patients with covi positive in a tissue / the total number of patients.
In addition, the duration of the virus in respiratory samples of patients with severe diseases is significantly longer than that of patients with mild diseases; there is no significant difference in the viral load in feces and serum samples of mild and severe patients.
There are significant differences in viral load among different tissues. Among the samples studied, respiratory samples had the highest viral loads, followed by stool samples, and serum samples had the lowest viral loads.
Through local weighted regression analysis, the researchers found that in the mild group, the viral load in the patient's respiratory tract sample peaked at the beginning of the second week of the disease; in the severe group, the viral load in the patient's respiratory tract sample was The third and fourth weeks continue to rise.
Similar to the trend of viral load in respiratory samples of critically ill patients, in the third and fourth weeks after the onset of the disease, the viral load of the patient's stool samples was the highest.
Since the onset of symptoms, changes in viral load in respiratory samples of mild and severe patients and all stool samples, purple represents respiratory samples of severe patients, yellow represents respiratory samples of mild patients, and pink represents stool samples of all patients
Viruses in lower respiratory tract samples last longer than upper respiratory tract, and peaks appear later
The researchers found that the researchers found that the type and duration of antiviral treatment had no overall effect on the duration and viral load of the virus.
In critically ill patients, the virus duration of patients receiving continuous glucocorticoid therapy for more than 10 days is much longer than that of patients with continuous treatment for less than 10 days. influences.
At present, the therapeutic effect of glucocorticoids and antiviral drugs on covid patients is unclear. The researchers emphasized that since the types and doses of antiviral drugs and glucocorticoids were not analyzed, the effects of antiviral drugs and glucocorticoids cannot currently be evaluated.
The authors said that in the next step, the effectiveness of antiviral drugs and glucocorticoids needs to be verified by more multi-centre randomized studies.
After stratifying the critically ill patients, the researchers found that the duration of the virus in males was significantly longer than that in females, and that in patients over 60 years old and male patients was longer.
In addition to the differences in the immune status of men and women, the causes of gender differences in virus duration may also be related to the differences in hormone levels. Part of the reason that the virus lasts longer in elderly patients is due to immune aging, and another reason is that the covi "receptor" angiotensin-converting enzyme 2 is higher in the alveoli of the elderly.
A previous study found that the peak load of covi in patients' upper respiratory tract samples appeared in the early stages of the disease. However, the researchers found that in the lower respiratory tract samples, the "viral shedding" of the new coronavirus lasted longer, and the peak appeared late, and the peak detoxification appeared only about two weeks after the onset of symptoms.
The researchers believe that these findings are important for effective control and prevention of the new crown epidemic, because this indicates that the entire disease process of covid patients must be strictly managed.
Based on the research results, the authors believe that the role of fecal excretion in the transmission of covid cannot be ignored. However, in the prevention and control of the covid epidemic, the feasibility of large-scale testing of stool samples also requires a comprehensive and careful evaluation.
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