Count your viruses
On the contrary: Rospotrebnadzor has created a test that determines the amount of coronavirus
Anna Urmantseva, Izvestia
In Russia, the first test has been created that allows us to detect not only the fact of the presence of coronavirus in biomaterial, but also its quantity. The development of the staff of the Central Research Institute of Epidemiology of Rospotrebnadzor will allow doctors to assess the degree of infection of the infected, predict the severity and duration of COVID-19, monitor the dynamics of the decrease in viral load and the effectiveness of treatment. Any biological material is suitable for the new test: smears from the nasopharynx and oropharynx, sputum, bronchoalveolar fluid, blood plasma. In addition, a set of reagents is suitable for the determination of SARS-CoV-2 on environmental objects with which infected people may have come into contact.
– This information will allow doctors and epidemiologists to obtain qualitatively new information about the degree of infection of the infected, predict the severity and duration of the disease, monitor the dynamics of the decrease in viral load, in other words, the effectiveness of treatment, – the head of the scientific group for the development of new methods for the diagnosis of acute respiratory infections and the reference center for monitoring the pathogens of upper and lower respiratory Tract of the Central Research Institute of Epidemiology of Rospotrebnadzor Svetlana Yatsyshina.
The new test allows detecting at least 500 copies of the virus genome in 1 ml of the test sample, the maximum amount of detected RNA is not limited, Svetlana Yatsyshina said. The concentration calculation with a given accuracy can be carried out in the range from 500 to 300 million copies of RNA in 1 ml, the specialist specified.
– Such sensitivity is common for modern methods of PCR diagnostics, - said Sergey Netesov, corresponding member of the Russian Academy of Sciences, head of the Laboratory of Bionanotechnology, Microbiology and Virology of NSU (a university participating in the program to increase the competitiveness of education "5-100"). – And its real capabilities will be shown only by practical experience of using the test in hospitals and ordinary PCR laboratories.
Deceptive asymptomacy
According to Rospotrebnadzor, in infected with SARS-CoV-2, the virus content in smears from the nasopharynx and oropharynx in the first days after the incubation period may be high even in the absence of symptoms of respiratory infection. This suggests that such people can actively spread the virus without knowing it. Thanks to the new test, they can be isolated in time. The kit can be used for screening infected people arriving in the country, detecting infected people during hospitalization in non-infectious hospitals and in infectious hospitals where COVID-19 patients are being treated.
In addition, the analysis is also important for those infected with signs of lung damage (pneumonia).
"The detection of SARS–CoV-2 coronavirus RNA in sputum in high concentrations correlates with a more severe course of the disease and is an unfavorable prognosis," explained Svetlana Yatsyshina. – On the contrary, a low concentration of coronavirus RNA or its rapid decline is a favorable sign.
On December 31 of last year, the FSUE TSNIIE received registration certificate No. RZN 2020/12597 for development until the end of 2021. The Institute has already produced the first registered series of reagent kits. Now the development is at the registration stage for obtaining an indefinite registration certificate in the Russian Federation.
The cost of the test is at the level of standard PCR with real–time detection, the specialists of Rospotrebnadzor specified.
Care for the lungs
Today, for most tests for coronavirus, smears from the nasopharynx and oropharynx are used, but it is possible to detect the pathogen in these materials only in the first days after the onset of symptoms. Therefore, a system that allows analyzing other biomaterials may be in high demand, experts interviewed by Izvestia indicated.
– As the experience of mass tests for the detection of RNA by PCR in 2020 has shown, the SARS-CoV-2 coronavirus, together with its RNA, leaves the nasopharynx and oropharynx within two to three days into the lungs, and it cannot be detected in nasal and oropharyngeal smears, - said Sergey Netesov. – Therefore, now in a number of countries they have switched to taking samples of sputum, feces and smears from the anus, since it turned out that it is actively multiplying in the intestine. So this diagnostic is useful and, I think, will be in demand, because it will allow detecting the pathogen RNA more reliably and for a longer period in comparison with a smear from the nasopharynx, oropharynx.
Alexander Zurochka, Head of the Laboratory of Molecular Biotechnology and Genetic Engineering at SUSU, agrees with him.
– The test created by the staff of the Federal State Budgetary Institution of the Central Research Institute of Epidemiology of Rospotrebnadzor expands diagnostic capabilities. The sensitivity of the test is high, so the development will be useful for detecting infection," the expert believes.
The new kit can also be used to examine environmental objects for the presence of SARS-CoV-2 RNA, Rospotrebnadzor told Izvestia. Any surfaces that, for example, an infected person has touched are suitable for analysis.
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