On March 23, local time, Chen Yu and Li Lanxuan from the National Key Laboratory for Infectious Disease Scare at the First Hospital affiliated with Zhejiang University Medical College published an opinion piece on the top medical journal, The Lancet Infectious Diseases, “SARS-CoV-2: Virus dynamics and host response”. Li Lanxuan, a member of the Chinese Academy of Engineering and director of the National Key Laboratory for the Diagnosis and Treatment of Infectious Diseases, is the author of the communication.
Li lanjuan et al. believe that knowledge of viral dynamics and host response is critical to developing strategies for antiviral therapy, vaccination and epidemiological control for COVID-19. However, research on these aspects has not yet formed a systematic system.
They evaluated a research paper published in The Lancet-Infectious Diseases on March 23rd by Kelvin Kai-Wang To et al. of the University of Hong Kong’s National Key Laboratory on New Infectious Diseases. Kelvin To and his colleagues reported viral loadands and antibodies in 23 COVID-19 hospitalized patients.
In these patients, the viral load peaks in the first week of the disease and then gradually decreases in the second week. Virus load is also age-related. In addition, IgG and IgM antibodies began to increase around the 10th day after the onset of symptoms, and most patients had serum transitions within the first 3 weeks. Finally, the levels of IgG and IgM antibodies for the binding domain of neo-viral nucleoproteins and surface S protein receptors were associated with neutralizing activity.
Li lanxuan and others commented that these findings have several practical implications:
First, the high viral load in the early stages of the disease indicates that the patient is the most infectious during this period, which may be the cause of the high transmission rate of the new coronavirus;
Second, the high viral load shows that the new coronavirus may be prone to antiviral resistance;
Third, the age in the above study was associated with viral load, which could explain the high incidence of serious diseases in patients with new coronavirus infection in old age. High viral load in older patients is not only associated with low immunity, but also with high expression of ACE2 receptors (cells entering the new coronavirus) in older adults.
In addition, the timing of antibody serum transformation is critical to determining the optimal time point at which serum samples are collected for diagnosis. This information is also important for immunologists to select the best time point for obtaining peripheral blood B cells for therapeutic monoclonal antibodies.
The main advantage of Kelvin To and his colleagues’ study was a systematic analysis of viral loadands and antibody spectra for four weeks, which provided insightinto into the interaction between virus escloser and host during acute and recovery periods, Li said.
Another noteworthy aspect is that the study used self-collected post-stophlyta samples, rather than nasopharyngeal samples, to monitor viral load. Collecting nasopharyngeal specimens is an invasive process that is uncomfortable for patients and poses a risk of infection for health care workers. Patients are more likely to receive self-collected saliva, and health care workers are safer.
They believe that this study clearly illustrates the feasibility of using saliva for viral load monitoring.
Mr. Li and others note that Kelvin To and his colleagues provided clinicians and scientists with reliable scientific evidence about COVID-19. Nevertheless, many problems remain to be addressed in terms of virus characteristics and host response during infection.
The new coronavirus has been detected in fecal, blood and urine samples, and determining the dynamics of viral load in these samples is also important for preventing and controlling pandemics. In addition, the relationship between viral load and disease severity needs to be further clarified.
They believe that a larger sample size study is needed to understand how different factors affect viral load or antibody response. For example, immunodeficiency patients may have a higher viral load, a longer detoxification process, and a damaged antibody response. In addition, future research for children’s populations is crucial, as children’s diseases appear to be much milder than adults’.
At the end of the article, Li lanxuan and his colleagues said that a more detailed understanding of the natural and adaptive immune response of the new coronavirus is important for understanding its pathogenesis and designing vaccines.