- April 9, 2022
- Posted by: OptimizeIAS Team
- Category: DPN Topics
Context: The recombination of novel coronavirus lineages is unlikely to be a greater threat to public health than mutations
How are variants created?
- SARS-CoV-2, the virus that causes COVID-19, is an RNA virus which evolves by accumulating genetic errors in its genome. These errors are produced when the virus infects a person and makes copies of itself inside the host’s cells.
- These errors (otherwise called mutations) are therefore a by-product of replication of SARS-CoV-2 inside the cell and may be carried forward as the virus continues to infect people. When viruses having a specific set of errors or mutations infect a number of people, this forms a cluster of infections descending from a common parental virus genome and is known as a lineage or a variant of the virus.
What is Mutation?
- A mutation means a change in the genetic sequence of the virus.
- In the case of SARS-CoV-2, which is an Ribonucleic acid (RNA) virus, a mutation means a change in the sequence in which its molecules are arranged.
- RNA is an important biological macromolecule that is present in all biological cells, Principally involved in the synthesis of proteins, carrying the messenger instructions from Deoxyribonucleic Acid (DNA), which is an organic chemical that contains genetic information and instructions for protein synthesis. It is found in most cells of every organism.
- A mutation in an RNA virus often happens when the virus makes a mistake while it is making copies of itself.
- Mutations are a natural phenomenon when viruses replicate.
- Generally, RNA viruses have a higher rate of mutations compared with DNA viruses.
- However, unlike other RNA viruses, coronaviruses have fewer mutations. This is because coronaviruses have a genetic “proofreading mechanism” that corrects some of the errors made during replication.
What is a recombinant variant?
- Recombination occurs when, in extremely rare situations, two different lineages of the virus co-infect the same cell in the host and exchange fragments of their individual genomes which generate a descendent variant having mutations that occurred in both the original lineages of the virus.
- Recombination of lineages happens in a variety of other viruses, including those that cause influenza, as well as other coronaviruses.
- Such recombination events occur typically in situations where two or more lineages of SARS-CoV-2 may be co-circulating in a certain region during the same time period. This co-circulation of lineages provides an opportunity for recombination to occur between these two lineages of SARS-CoV-2.
Are recombinant variants more deadly?
- Although recombination has been detected in SARS-CoV-2, it has not yet impacted public health in a unique way. There is little evidence to suggest that recombinant lineages have a varied clinical outcome compared to the currently dominant Omicron variant, although preliminary data from the U.K. health security agency suggests a transmission advantage over the Omicron variant.
- It is certain at this point in time that more data will be needed to ascertain the impact of these lineages on the epidemiology of COVID-19.
- When there is multiple lineages circulating, the danger is that the viruses could combine one dangerous phenotype with another dangerous phenotype into a single virus that has two dangerous phenotypes