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AUTHOR: SULTANA YEASMIN
Introduction
The coronavirus pandemic has everyone on edge, placing a halt into society. To ensure the safety of all, people should wear masks, stay at least 6 feet apart from each other, and wash up after coming home from outside ("How To Protect Yourself And Others"). However, if a person catches symptoms of the disease, they must go to a lab and get tested. During testing, many molecular biology concepts are placed into factor to evaluate one's contact with SARS-CoV-2, the virus that causes the disease. Testing for COVID-19 is essential to flatten the curve, not just for Americans but also for all humans around the globe.
Why is Testing Important?
Testing is one of the most crucial factors to aid in the reduction of the spread of the coronavirus. During the early stages of a virus, thorough testing "leads to quick identification of cases, quick treatment for those people, and immediate isolation to prevent the spread" (Sanchez, 2020). An ideal situation would include a "team of soldiers" who would find patients exposed to the virus, isolate them at home, and find people they have contacted, ensuring the safety of all.
The US did not have many resources ready for the pandemic, which was why numbers were growing at such exponential rates. In particular, the low number of equipment to run COVID-19 tests, the significant amount of time to provide results, and the federal government's lack of help were the most significant issues that led to the soaring death rates in America. Although the United States of America did not prioritize testing initially, officials soon realized its significance and quickly hopped on. As of right now, approximately 32.3 million tests have been taken for COVID-19, and of those, about 3 million were reported positive ("Testing In the US"). Also, through the testing and reports, more data will become prominent. Examples of such are how the coronavirus has disproportionately impacted low-income neighborhoods and people of color.
For an even greater understanding of how necessary testing is, we can compare the actions and outcomes of the US and South Korea, a country in Asia that began widespread testing and contact tracing during the beginning of the coronavirus outbreak (Hasell, 2020). The peak of cases in South Korea was around mid-March, whereas America's peak was one month later. To further emphasize this comparison, the number of confirmed cases in America today is around 2.5 million, and the total deaths are about 125 thousand ("CDC COVID Data Tracker"). On the other hand, in South Korea, there are about 12.5 thousand confirmed cases and about 280 deaths ("South Korea"). Statistics conclude that there are about ten times as many deaths in America than there are confirmed cases in South Korea, due to the difference in testing and control during the start of the pandemic.
Types of Testing for COVID-19
There are two different types of testing for COVID-19, diagnostic tests and antibody tests. Diagnostic tests can tell a patient whether they have an active coronavirus infection, but cannot tell if they have experienced it in the past. There are two types of diagnostic tests—molecular tests, which detect a virus' genetic makeup, and antigen tests, which detect viral proteins in a sample. Molecular tests, or RT-PCR tests, are useful and accurate, whereas antigen tests have a higher likelihood of being incorrect ("Coronavirus Testing Basics"). On the other hand, antibody tests can do the opposite; they can tell if a patient has previously been exposed to the coronavirus, but cannot tell if it is active. Just as the name implies, antibody tests search for the virus' antibodies in a patient's sample, allowing scientists to understand that the patient has been exposed to the virus and their immune system has already fought against it. In this essay, we will only be focusing on the PCR test, which falls under molecular tests.
PCR / RT-PCR Tests
Though there are many types of tests available to evaluate one's contact with the virus, one of the most commonly used methods is the PCR or Polymerase Chain Reaction Tests. PCR tests work to synthesize millions of DNA copies for scientists to analyze and trace specific genetic material. However, in the case of SARS-CoV-2, which uses RNA as its code, scientists must use RT-PCR (Reverse Transcription Polymerase Chain Reaction). In this case, rather than using transcription—a biological process that uses a DNA template to synthesize an RNA molecule— reverse transcription is used, so that complementary DNA strands are made from RNA templates.
First, a patient's sample is collected, and their RNA is isolated. Then, the viral RNA is mixed with other enzymes like DNA polymerase and reverse transcriptase, DNA building blocks, primers, and more, to form a solution that will help mimic the natural way that DNA proliferates in an organism. Through a series of steps that synthesizes DNA replication, a viral DNA template that is complementary to the first RNA strand is created (Tiner, 2020). Then, the DNA strands are heated and separated, allowing the process to repeat twice more. This process repeats continuously, doubling the number of DNA strands until scientists are satisfied. If any of the DNA copies are complementary to SARS-CoV-2, the primers will copy the detected region, causing probes to attach to the fragments and create a signal for the PCR test to read positively. This signal implies that the patient has SARS-CoV-2, meaning that they have the coronavirus. However, if the probes do not attach to any strand of DNA, then the PCR test will read negative, meaning that the patient is free from the virus.
Even while the PCR tests seem like a tremendous biotechnical tool to help us during this tough time, there are always advantages and disadvantages to every device. For example, the tool is straightforward and produces results pretty quickly. However, PCR tests can only identify a known gene/pathogen, are costly, and "any form of contamination of the sample by even trace amounts of DNA can produce misleading results" (Garibyan et al., 2020).
All in all, testing plays a massive role in flattening the curve for COVID-19. So far, ever since testing numbers have increased nationally and internationally, the infection and death rates have decreased. Hopefully, through social distancing, testing, and looking after ourselves, the world can bounce back from the pandemic, even more robust than ever!
Works Cited
“CDC COVID Data Tracker.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 27 June 2020, www.cdc.gov/covid-data-tracker/#cases.
“Coronavirus Testing Basics.” U.S. Food and Drug Administration, FDA, 10 June 2020, www.fda.gov/consumers/consumer-updates/coronavirus-testing-basics.
“How to Protect Yourself & Others.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 24 Apr. 2020, www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/prevention.html.
“South Korea.” Worldometer, 27 June 2020, www.worldometers.info/coronavirus/country/south-korea/.
“Testing in the U.S.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 25 June 2020, www.cdc.gov/coronavirus/2019-ncov/cases-updates/testing-in-us.html.
Garibyan, Lilit, and Nidhi Avashia. “Polymerase Chain Reaction.” The Journal of Investigative Dermatology, U.S. National Library of Medicine, Mar. 2013, www.ncbi.nlm.nih.gov/pmc/articles/PMC4102308/.
Hasell, Joe. Testing Early, Testing Late: Four Countries' Approaches to COVID-19 Testing Compared. Our World in Data, 19 May 2020, https://ourworldindata.org/covid-testing-us-uk-korea-italy.
Sanchez, Eduardo. “COVID-19 Science: Why Testing Is so Important.” Www.heart.org, American Heart Association, 2 Apr. 2020, www.heart.org/en/news/2020/04/02/covid-19-science-why-testing-is-so-important.
Tiner, Sara. “The Science Behind the Test for the COVID-19 Virus.” Https://Discoverysedge.mayo.edu/, Discovery Edge, 31 Mar. 2020, https://discoverysedge.mayo.edu/2020/03/27/the-science-behind-the-test-for-the-covid-19-virus/.
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