By: MKHUNJULWA DHLAMINI C.B.
In getting to understand COVID 19, it is important to understand its origin as well as its mutation in order to best know how to combat it. Coronaviruses are not new and in fact are a cluster of viruses that have existed for a long time. However, the novel Coronavirus currently plaguing the planet is one of several known to infect humans.
Scientists have divided coronaviruses into four subgroups namely, Alpha, Beta, Gamma and Delta, with seven of these viruses able to infect people. These are, 229E and NL63 both belonging to the Alpha group; OC43 and HKU1 in the Beta group; MERS-CoV, SARS-CoV and finally SARS-CoV 2 which causes COVID 19.
Strains happen when the genetic material of the viruses (RNA) infect a host, copy the RNA of the cells they infect and change or mutate. This is all natural and normal when viruses multiply and spread. If a virus has a change that makes it easier to infect people and spread, then a variant becomes common. The Brazilian strain of COVID 19 for example, has mutated so as to help it evade the antibodies that fight the coronavirus.
Part of what has made the fight to combat COVID 19 as well as the reason for so many vaccines, is the differences in mutated strains on different continents as well as the spread of new strains. Research has pointed to various strains in South Africa, Brazil as mentioned previously, the UK, Nigeria amongst other countries.
Earlier variants of the virus were identified by researchers in China who studied 103 different samples in animals and humans and found two major variants, L and S. However, four other strains are also present which are the GH, R, V and G strains. The L Strain is the original strain found in Wuhan but is disappearing and only accounts for 7% of cases worldwide most of which are in Asia.
The S Strain which was the first mutation of the L strain, is also in decline and only accounts for 8% of cases worldwide the bulk of which are in the Americas. The V Strain, much like the L Strain, is slowly disappearing and is responsible for 8% of cases worldwide mostly in Europe. The G Strain is by far the most widespread of the virus and has mutated into the GH and GR Strains. The G Strain and its mutations account for 74% of all gene sequences and two of the mutations can cause a spike in protein as well as a change in RNA polymerase.
The GR Strain is the most commonly found strain and accounts for 29% of cases worldwide, most of which occur in Europe and South America. The aforementioned spike in protein allows this strain to enter human cells more readily. Last is the GH Strain which is predominant in the USA.
Sources:
The New England Journal of Medicine: “Neutralizing Activity of BNT162b2-Elicited Serum.”
Up to Date: “Patient education: Coronavirus disease 2019 (COVID-19) overview (The Basics).”
The Washington Post: “Pfizer-BioNTech vaccine may neutralize Brazil variant, lab study finds, as experts warn of rapid spread.”
BBC: “Covid Brazil variant 'may spread more easily.’”
Healthday: “Pfizer COVID Vaccine Shows Mettle Against Brazilian Variant.”
Virological: “SARS-CoV-2 reinfection by the new Variant of Concern (VOC) P.1 in Amazonas, Brazil.”
CDC: “Coronavirus disease 2019 basics,” “Key facts about seasonal flu vaccine,” “Human Coronavirus Types,” “New COVID-19 Variants,” “About Variants of the Virus that Causes COVID-19 ,” “SARS-CoV-2 Variants.”
National Institutes of Allergy and Infectious Diseases: “Coronaviruses.”
Nature Medicine: “The proximal origin of SARS-CoV-2.”
World Health Organization: “Coronavirus.”
Methods in Molecular Biology: “Coronaviruses: An Overview of Their Replication and Pathogenesis.”
Historyofvaccines.org: “Viruses and evolution.”
Nature: “A new coronavirus associated with human respiratory disease in China,” “We shouldn’t worry when a virus mutates during disease outbreaks.”
National Science Review: “On the origin and continuing evolution of SARS-CoV-2.”
European Centre for Disease Prevention and Control: “Rapid increase of a SARS-CoV-2 variant with multiple spike protein mutations observed in the United Kingdom.”
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