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Research team led by YCU professor successfully develops a rapid diagnostic test for COVID-19 that can detect antiviral antibodies in patient serum

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The illustration above shows the novel coronavirus that causes COVID-19. Image courtesy of Centers for Disease Control and Prevention of the United States of America.





Research team led by Yokohama City University professor successfully develops a rapid diagnostic test for coronavirus disease 2019 (COVID-19) that can detect antiviral antibodies in patient serum.



COVID-19, the disease caused by the novel Corona virus ‘Severe Acute Respiratory Syndrome Coronavirus 2’ abbreviated as SARS-CoV-2 happens to be the most recent threat to mankind causing major public health issues. Breaking out of all the containment efforts, the virus has spread across international borders to cause a massive pandemic. Urgent measures are required to tackle this outbreak as countries worldwide have reported over 500,000 infections and 20,000 deaths*.

* as of March 27, 2020


As the complete details about the nature and pathogenicity of the virus still remains enigmatic, it would be wise to limit new infections as much as possible. Despite the urgency of the situation, rapid diagnostic methods and serum antibody diagnostics that can be used to screen large populations and rule out infections have not been established. Current screening methods for COVID-19 are based only on medical examination for the presence of clinical features such as fever and cough and history of exposure or travel. This could possibly miss out a few truly infected people who could disseminate the disease in the community, thereby propagating the outbreak. The polymerase chain reaction (PCR) which is the only available test at present to diagnose COVID-19 cannot be used to perform on a multitude of patients. This further underscores the need of simple and rapid diagnostic tests.

 
 

"A research group led by Professor Akihide Ryo of Yokohama City University Graduate School of Medicine’s Department of Microbiology has successfully ... developed Enzyme-Linked Immunosorbent Assay (ELISA) and a rapid immunochromatographic test which can specifically detect the IgG SARS-CoV-2 antibodies."

 

A research group led by Professor Akihide Ryo of Yokohama City University Graduate School of Medicine’s Department of Microbiology has successfully devised diagnostic methods to detect antiviral antibodies (IgG) in the serum of persons with COVID-19 infections. The team has developed Enzyme-Linked Immunosorbent Assay (ELISA) and a rapid immunochromatographic test which can specifically detect the IgG SARS-CoV-2 antibodies. The rapid test uses the same mechanism as the pregnancy test strip where serum can be added to get colored lines to interpret the result. Due to the speed and simplicity, this could be useful as a Point-Of-Care Testing (POCT) device for COVID-19 screening.

In general, IgG antibodies are elevated after 1 week following the onset of the disease and may not necessarily reflect the current infection status. However, in many cases, the incubation period of COVID-19 is relatively long, ranging from a few days to about 2 weeks, and symptoms appear as a mild flu like illness at first and progresses to breathlessness and pneumonia in approximately 5-7 days. So, by the time a person develops fever and breathlessness due to COVID-19, they would invariably contain the IgG antibodies in their serum. Therefore, these serological tests would be instrumental in arriving at a diagnosis to provide a way for further management.

Preliminary analysis of these testing kits was done using clinical samples from six patients with COVID-19 that were infected for 10 days or more. All these patient samples were PCR-positive and showed positive reactions for serum IgG by both ELISA and immunochromatography. In addition, these antibody assays can be used in future epidemiological studies as tools to retrospectively test for the presence or absence of a history of COVID-19 infection.


 

“Both these tests are blood-based diagnostics, which makes it easier to collect specimens and carry a lower risk of secondary transmission to health care workers, laboratory personnel and others who are involved in specimen collection and handling."

 

ELISA assay quantitatively analyzes the titer of antibodies with a high sensitivity of detection and is suitable for processing multiple samples. It can also be used to analyze the antibody levels in paired serum to assess treatment efficacy. On the other hand, immunochromatography can provide qualitative analysis by visual judgement, which makes it possible to identify SARS-CoV-2 infection in a short time without the need for special equipment. Both these tests are blood-based diagnostics, which makes it easier to collect specimens and carry a lower risk of secondary transmission to health care workers, laboratory personnel and others who are involved in specimen collection and handling.

Professor Akihide Ryo also reiterates that further studies with a larger sample size would be necessary, before considering these tests as diagnostic methods and/or Point-Of-Care Testing (POCT) devices. If this could be achieved, these tests can serve as rapid diagnostic methods that can be performed at the outpatient clinics or bedside and improve accuracy in patient diagnosis. Combining them with PCR will enable the scope for more appropriate and accurate management strategies.

Considering their tremendous potential, these serodiagnostic methods for the new coronavirus warrant to be refined by empirical research in collaboration with relevant organizations. At present, the results of this study have not been approved for in vitro diagnostics by the Act on Securing Quality, Efficacy, and Safety of Pharmaceuticals and Medical Devices, and is still in the stage of empirical research.

 

For further information, please contact the Research Planning and University-Industry Cooperation Division of Yokohama City University at kenkyupr@yokohama-cu.ac.jp