Your guide to understanding the SARS-CoV-2 variants: what’s the business about them?

You hear it all of the news; the South African variant, the Brazilian variant, the UK variant and now even the Californian variant. To make it easier to understand what's going on, I’m going the debunk some myths about the variants and seeing how they form, their effects and whether the different vaccines can still offer protection against them.

So, what is a variant of ANY virus?

Viruses are just like any other microorganisms, in the sense that they must reproduce in order to continue surviving, as do humans. However, they cannot provide the proper processes needed to copy their RNA (the nucleic acid and the 'framework' as to where the viral genome is found). Therefore, upon infection, to maintain survival, they must 'hijack' a host cell which is much more complex and can provide the 'machinery' and actions required to copy the RNA to produce virions: a singular virus particle. Once the cell has been taken over, many of the sub-cellular structures that help in the process of making the DNA required for the organism itself start functioning to only make copies of the virus. However, this process is much quicker and intense than can be imagined; a singular cell can produce up to a million virions when taken over. Therefore, genetic mutations, which could change the infectivity rate, symptoms and intensity of the disease is practically inevitable and hence why many variants of any virus coexist around the world. Although one singular change in the RNA of the copied virus may not change anything and lead to a 'silent mutation' where the effects of an error in its duplication may not be observable, there are chances of multiple mutations occurring, which can lead to big changes in the RNA of the virus.

What happens when it all goes wrong?

So let's say that within the body of a single human or host, a genetic mutation has occurred in the RNA of the virus and is spreading to another person where the 'faulty' RNA sequence is being copied and duplicated millions of times in their cells too. Depending on whether this variant is solely a variant or a strain, it may have different effects.

A variant is a mistake in the genetic code, where the RNA sequence may not be the same as the original, parent virus however it may not have any physical effects on a person and the infection they suffer as a result of a variant. However, when these mutations result in a physical characteristic or behaviour of the virus being changed, it can then be referred to as a variant. So a strain is a variant but not the other way around.

In short, a variant may be able to spread faster and be more transmissible in certain environments however a strain may affect the intensity and duration of the virus.

The UK Variant - B.1.1.7

Normally variants don't have too extreme effects on patients as we can see from the B1.1.7 (more commonly known as the UK, or Kent) variant which emerged in the early-mid autumn of 2020, where patients didn't suffer too extremely from the variant however it was much more transmissible. Scientists claim this variant is the reason behind the sharp rise in infections in late 2020 and early 2021 in the UK.

Here it's clear to see that the B.1.1.7 variant has lead to a high of a maximum of at least 68,000 new cases a day in early December, which is 8.7 times higher than the peak case number in April 2020 (7,800 maximum cases in one singular day) from the original SARS-CoV-2 parent virus.

The reason for the transmission rates being higher for the UK variant is due to the mutation coding for the spike proteins also named the N501Y mutation which is present in the South African variant too. The N501Y variant is due to an amino acid asparagine being replaced with tyrosine, therefore a possible theory is that the spike proteins that land of cell receptors are more easily attached therefore increasing the transmissibility of the variant as it can attach to the site much quicker.

Although many viruses, including COVID-19, have many variants, it's quite early to make conclusions about whether it leads to a more intense infection or whether it has a higher mortality rate than the original novel coronavirus strain which emerged from Wuhan, China in late 2019.

Do vaccines still offer protection against the different variants?

The B.1.351 variant (also known as the South African variant) has the same N501Y mutation as the UK variant however also includes an E484K mutation within its RNA sequence, meaning that vaccines may be less effective in preventing the Brazilian variant of COVID-19 in comparison to other variants as it helps to evade the immune system. This means that antibodies may not be able to bind to it as well as they should therefore it cannot be neutralised too well so cases may still occur after the vaccine. However, new claims support that the Pfizer vaccine may be suitable to protect against all variants, regardless of how they have mutated after 2 doses.

The COVID-19 variants are a cause of concern nowadays, however with social distancing and taking preventative measures, chances of contracting any virus reduce the chances of further mutations from taking place. Scientists do not know as of now fully how deadly or intense the current and rapidly emerging new variants can be to humans and their mortality rates; lots of intensive research must be done on this.

9th March 2021

SOURCES:

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