Appropriate Screening Tests of Asymptomatic Patients is the Current Requisite to Check Novel Coronavirus Infection

Neucrad Health June 22, 2020

The disease that has been spreading aggressively among people around the world and is a constant source of worry for the past months is Covid-19. So far, more than 82 million people worldwide have been infected and more than 4 million have died. However, these numbers are not stable. Unknowingly, healthy people are being affected in each passing days. The microorganism, SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2) is silently increasing the incidence of the disease. Despite several stringent rules, strict discipline of social distancing, Coronavirus infection is on the rise. So, what’s going on?

To find the answer to this question, we need to discuss one of the special features of the Covid-19 infection. Clinically, Covid-19 positive people are mainly divided into two groups. One: those who have symptoms of the disease, i.e. ‘symptomatic’ and Two: those who do not have the symptoms of the disease, i.e. ‘asymptomatic’. People with symptoms like fever, cough, diarrhea, shortness of breath, etc. are being admitted to the hospital, their blood tests are showing the presence of coronavirus and treatment is going on. According to the rules of the World Health Organization (WHO), all these patients and those who have mild symptoms should be identified immediately and kept in isolation for immediate treatment. Now the problem is with the second group of people, that is, those without symptoms. If they are infected with Covid-19, it is impossible to detect the presence of virus in their blood and sputum tests. As a result, their identification becomes difficult. Unbeknownst to them, they continue to infect healthy people and corona continues to spread silently!

Recently, a study from Chongqing Medical University in China has drawn considerable attention from scientists worldwide. The research team of the University’s Laboratory of Molecular Biology on Infectious Diseases, under the supervision of Professor Ai-Long-Huang, conducted a test in patients with asymptomatic and clear symptoms and presented exciting data. According to them:

1. An infected but asymptomatic person with Covid-19 does not develop a good immune response. In particular, the level of cytokines, chemokines in the body decreases.
2. Also, the only right way to detect the presence of SARS-CoV-2 nucleic acid with reverse transcription polymerase chain reaction or RT-PCR technology. However, this method is costly.
3. So, what is the way-out? According to the researchers, blood tests can detect specific SARS-CoV-2 antibodies in a patient’s body after infection as well as during convalescent time periods. Such a method is known as ‘serological testing’. With Covid-19 infection, the body begins to produce antibodies, primarily Immunoglobulin-G (IgG) and Immunoglobulin-M (IgM), to fight against the virus. According to Professor Huang’s research, IgG is produced 16 to 19 days after the onset of the infection and IgM antibodies are produced in the patient’s body within 20 to 22 days. Thereafter, the amount of IgM decreases slightly. However, by reviewing the levels of these two antibodies through serological tests, it is possible to determine the rate of corona infection in an asymptomatic patient.

The researchers’ remarkable work was published in the June 17^th issue of the journal “Nature Medicine”. Undoubtedly, their research data is extremely important for preventing corona infections universally. In the next few days, this ‘serological testing’ could become a landmark step in identifying asymptomatic corona positive patients and help to fight against Covid-19 successfully.

References:

1. Long QX, Tang XJ, Shi QL, et al. Clinical and immunological assessment of asymptomatic SARS-CoV-2 infections [published online ahead of print, 2020 Jun 18]. Nat Med. 2020;10.1038/s41591-020-0965-6. doi:10.1038/s41591-020-0965-6
2. https://www.who.int/emergencies/diseases/novel-coronavirus-2019/technical-guidance/infection-prevention-and-control
3. https://www.statnews.com/2020/06/09/who-comments-asymptomatic-spread-covid-19/

Author Profile:

Dr. Shuvomoy Banerjee

Dr. Shuvomoy Banerjee has been teaching as Assistant Professor in the Department of Virology and Immunology at Amity University, Delhi. He holds a PhD degree in Cancer Biology from Jadavpur University and later did postdoctoral research in Viral Oncology from University of Pennsylvania School of Medicine as well as from City of Hope National Cancer Institute (California). Recently, the author has been involved in teaching, writing, cancer research and awareness program.