COVID-19 Variants and Mutations

Shreya Sarathy
4 min read

For over a year now, COVID-19 has dominated world news. From vaccines to variants, there is a constant influx of new and changing information from many sources. In recent weeks, the infamous Delta variant has featured prominently, causing a lot of confusion and concern. To that end, it might be helpful to take a look at what COVID-19 variants actually are, why they are a concern, and how worried we should be about them.

Mutations and Variants- What’s the difference?

A mutation is a change in the viral RNA sequence. The viral genome with a mutation is called a variant. COVID-19 has shown a relatively low mutation rate, particularly for an RNA virus, which tend to mutate faster than DNA viruses. This could be due to the low natural selection pressure the virus has experienced- so far, it has had very little difficulty with infecting and spreading rapidly. The fact that we are seeing so many variants despite this is indicative of how far the COVID-19 situation has been allowed to spiral; there are viruses with a lower mutation rate that lead to less mutants in the same amount of time, but due to the sheer number of infections, COVID-19 has produced a large number of variants even with a low mutation rate.

Image: SARS-CoV-2 spike (Institute for Nanostructure – University of Hamburg).

Variants are currently being classified under two labels: variants of interest (VOI) and variants of concern (VOC). Variants of interest are variants with genetic changes that are predicted to make the virus more infectious or harmful and which have significant prevalence. Variants of concern meet the definition of a VOI while also being associated with one or more of the following: an increase in virulence, an increase in transmissibility, or a decrease in effectiveness of public health measures.

Variants of Concern- Alpha, Beta, Gamma

The alpha variant (also called the B.1.1.7 variant) first appeared in the United Kingdom in September of 2020. It has since become the most common variant, having spread across more than 50 countries. This variant is more contagious than the original virus, with an increased transmission rate of around 50%. Available COVID-19 vaccines have proved effective against this variant.

The beta variant (or B.1.351) was first detected in South Africa. The beta variant has two main features that make it concerning: a 50% increase in contagiousness, making it easier to transmit, and a particular mutation (E484K) nicknamed the “Eek” mutation which makes it easier for the virus to evade the body’s immune response. While it never gained a foothold on a global scale, it quickly became the dominant variant in South Africa and posed a significant obstacle to vaccine rollouts there. AstraZeneca’s vaccine, which was the primary vaccine available in South Africa, was found to have severely reduced efficacy against this variant. J&J, Pfizer and Moderna also reported reduced protection from these strains.

The gamma variant (or P.1) was first reported in Brazil. After a devastating second wave in late 2020, this variant became the most prominent one in Brazil, making up around 90% of cases there. It also spread to Chile and other South American countries and, to a lesser extent, to the US and UK. This variant shares some features with the beta variant, including the Eek mutation and an increased transmissibility rate (approximately 1.5-2 times higher). All vaccines have so far proven to work against this variant, despite being slightly less effective.

The Delta Variant

The final and most recent variant of concern, the delta variant (also known as B.1.671.2), first appeared in India in late 2020. It contributed significantly to the devastating effect of COVID-19 there, and has since rapidly spread all across the globe, sparking fear and furor.

The highly increased transmissibility of the delta variant is a reason for this sudden wave- this variant is 50% more contagious than the alpha variant, making it the most contagious variant so far. The variant also has two mutations of note which contribute to its VOC designation, which is why it has been referred to as a “double mutant”. The L425R mutation is predicted to help the virus bind more effectively to human cells. The E484Q mutation serves a similar function to the E484K or Eek mutation in the beta variant, helping the virus evade the body’s immune response and thus potentially making it easier for vaccinated or previously infected people to fall sick again.

Existing vaccines have proven to be effective against this variant and, in most cases, prevent life-threatening illness. While this is good news, it does mean this variant particularly concerning for those in areas with low access to healthcare who may not have been vaccinated yet. Due to its incredibly rapid spread, the virus could very quickly infect and decimate whole communities.

Image: Mapping mutations on B1.617.2 and other variants of concern.

Looking to the future

While the delta variant has taken over the news cycle for now, there is another potential variant of concern looming on the horizon. The lambda variant was first identified in Peru late last year. As of now, it is designated as a variant of interest, not of concern, but experts have said this is the variant they’re watching closely. Like previous variants, it appears to have a higher transmissibility than the original virus.

Somewhat more alarming is the fact that so far, data is split on whether or not current vaccines are effective against this variant. Some sources report that this variant may be able to evade vaccine antibodies, while others report that the variant shows little resistance against them. Overall, more research is needed before we can definitively state that there is a cause for concern, but caution is still heavily advised in the meantime.

The main thing we can do to prevent the spread of these new variants is to continue doing what we have been doing for the last year. It is recommended that even vaccinated people continue to wear masks and social distance when the vaccination status of companions is unknown. And, of course, those for whom vaccination is an option should absolutely try their best to get one of the available vaccinations. Unvaccinated people are far more vulnerable to all of these variants, and getting everyone immunized is our best chance at finally being able to return to normal.

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