Abigail BanerjiFebruary 26, 2021 09:17:26 IST
With ‘Mrs. Rona ‘, better known as coronavirus, celebrating its first anniversary since it entered our lives, terms like pandemic, PPE, antibodies, antigens, etc. have grown in demand and popularity and are now part of our daily vocabulary. Many of us can now understand the complex process of a developing vaccine, the clinical tests it goes through and the regulatory approvals it would need before it is launched. We live and learn.
With the SARS-CoV-2 virus rapidly ‘mutating’, new ‘variants’ of the virus have emerged in many parts of the world. In the pre-COVID-19 era, we could have used this new piece of information to impress friends or family during dinners or cocktails. But let’s be honest, the variants in question probably won’t allow that to happen anytime soon.
So let’s dive in and understand the basics …
what is a virus?
Before the COVID-19 pandemic, we vaguely heard about viruses that cause diseases like Ebola in Guinea and Congo, swine or bird flu in India and Russia, AIDS, etc. Now we know that the SARS-CoV-2 virus causes the COVID Disease of -19.
According to a Scientific American, the scientific community for many years has debated about the definition of a virus; first as a poison, then a life form and then a biological chemist.
Today, viruses are considered to be something between a living thing and a non-living thing.
ONE virus it consists of a nucleus of genetic material (DNA or RNA) surrounded by a protective protein layer. They can attach themselves to host cells and use the host cell’s machinery to multiply their genetic material. Once the replication process is complete, the virus leaves the host by budding or exploding the cell, destroying it in the process.
Viruses cannot replicate on their own, but once they bind to a host cell, they can thrive and affect the host cell’s behavior in a way that damages the host and benefits the virus.
What is a tension?
A strain, according to a report in the The conversation, is a variant built differently, shows different physical properties and behaves differently from the original virus. These behavioral differences can be subtle or obvious.
Coronaviruses, such as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), are studded with protein “spikes” that bind to receptors on their victims’ cells. SARS-CoV-2 is now one of several other well-known strains in the coronavirus family, including the SARS and MERS viruses.
Experts believe that the term tension is often misused.
“There is a coronavirus strain. This is SARS-CoV-2. This is the single strain, and there are variants of that strain.” The Independent quoted Professor Tom Connor of the School of Biosciences at Cardiff University as saying.
What is a mutation?
A virus is made up of a sequence of DNA or RNA, which is basically a sequence of letters of nucleotides that encode genes in all living things. Any change in these letters is called a mutation and occurs when a virus sequence replicates. Mutations occur very randomly in a virus – a fact that can work for or against us in a pandemic scenario. A mutation can be beneficial for the virus and make it stronger, or it can be harmful and reduce its virulence.
SARS-COV-2, unlike the influenza virus, has a protein known as a revision enzyme. The enzyme is similar to what a text editor does in a newspaper, that is, checking for misspellings on a page. This enzyme will make corrections, based on the sequence of the source virus. Therefore, if there was any change due to a random mutation, he will try to correct it.
Like a human text editor, sometimes a mutation can pass through the proofreading enzyme and remain. As the particle of the mutant virus replicates, its entire genome, including the site of the mutation, is duplicated and transported by future generations of the virus.
So, how do you know if the virus has mutated? That’s where a virologist comes in. Virologists have been working tirelessly to sequence all the variants that infect people. The original virus, found in Wuhan, is being used to compare mutant variants of the coronavirus.
What is a variant?
Simply put, “a variant is a version of the virus that has accumulated enough mutations to represent a separate branch in the family tree”, it says infectious disease specialist Dr. Amesh Adalja senior fellow at the Johns Hopkins Center for Health Security.
Each mutation and strain of a virus is a variant, but each variant is not a strain.
Most variants are not a cause for concern. This is because the mutations did not cause any drastic changes in the virus in question. However, when multiple mutations occur, it can sometimes affect the way the virus behaves, spreads or infects people. It is when a variant becomes a ‘concern variant’. A classic example is the new variants that are spreading across parts of the UK, Africa and Brazil.
Scientists are looking at variants of SARS-CoV-2 to understand how genetic changes in the virus can affect its infectivity (and therefore its spread), the severity of the disease, the treatment and the effectiveness of available vaccines, it says Dr. Thomas Russo, professor and chief of infectious diseases at Buffalo University in New York.
What are the new variants in circulation?
A variant of SARS-CoV-2 known as B.1.1.7 has been spreading across the UK since December 2020 and cases are now emerging around the world. Scientists have found some evidence that this variant has an increased risk of death compared to other variants.
An infographic that talks about all the latest spreading SARS-CoV-2 variants. Image credit: European Center for Disease Prevention and Control
In South Africa, another variant of SARS-CoV-2 known as B.1.351 has emerged. It has some similarities to the UK variant and can also reinfect people who have recovered from other variants of COVID-10. There is also evidence that the AstraZeneca and Moderna vaccine is not as effective against this variant.
A variant known as P.1 emerged in Brazil and was first discovered in people traveling from the South American country to Japan. There is some evidence to suggest that this variant may affect the way antibodies react with the virus. The mutation of the P.1 variant prevents the antibodies from recognizing and neutralizing the virus.
According CDC, all three variants share a specific mutation called D614G, which allows it to spread more quickly.
With new variants constantly emerging, it is important that we are at the top of our genome sequencing game. By doing so, we will be able to find new variants that are of interest to public health (as they can be more infectious, cause more serious illnesses, develop a vaccine or immune resistance) and we can get ahead. However, ignoring these new emerging mutations will not make them disappear and can be harmful to us in the long run.