After over a year of the reporting of initial few cases of coronavirus in China, the virus has comfortably managed to spread to the entire world including Antarctica. As if that was not enough, researchers have found mutations of Covid-19, indicating that the virus is here to stay. Mutation occurs when a virus undergoes changes while multiplying. As the virus replicates, it may not produce exact replicas, resulting in the emergence of new strains, which might or might not be less effective. In this process, few strains die out but the more effective ones, which spread efficiently, survive. Every once in a while, a virus gets lucky and mutates in a way that helps it survive and reproduce. As a matter of fact, the more diverse a species is, the more chances it has of survival. Similarly, as viruses mutate, their chance of survival increases.

All viruses have a natural tendency to mutate over time. Every COVID-19 infection is a potential opportunity for the virus to mutate. Therefore, a rise in number of infections also means a rise in new variants as well. Presently, there are three major known variants: South African variant, known as B.1.351; the British variant known as B.1.1.7 and the Brazilian variant: P.1. Though there may be multiple strains floating, these are the dominant ones which have evolved over the course of the pandemic. The South African variant has undergone several changes in the spike (S) protein. The British variant, which is more infectious, but not necessarily more deadly than others, was likely to become the most dominant global strain. Initially detected in Kent, a British region close to London, it has now spread to more than 50 countries. The strain’s high transmissibility led to enforcement of fresh lockdowns in UK and led to global panic. 

It is evident that these strains are deadly and far more contagious. Their increased transmissibility can cause severe diseases and can also lead to more patients catching the disease twice. But it is still unknown that how differently the mutations of Covid-19 infect and sicken people. Meanwhile, it has also been established that there are chances of an individual getting infected with two strains of a virus at the same time, also known as co-infection. The impact of COVID-19 in terms of hospitalizations and deaths is high, especially for the elderly and those with co-morbidities. As a result, with much more contagious strains, health systems would be overwhelmed again by a rapid rise in cases. 

Even as we have lived with the pandemic for more than a year, the question still remains. What exactly is causing the virus to mutate into more contagious and deadly forms? Viruses have a natural tendency to mutate. When the virus clings to human cells, it needs to replicate itself. However, all of its duplications aren’t perfect, hence, mutations occur. Not all mutations have an impact on the physical form or behavior of the virus. Some of the mutations can cause a change in the way it causes disease – its intensity and transmissibility. Moreover, the immune system tries to kill the virus once detected in the body. The virus strain that persists in the population is the one that gets away by dodging the immune system. The fact that new mutations of Covid-19 have been detected in areas with high cases is a testimony that mutations have occurred in places with high levels of immunity.  

Moreover, different regions of the world have exposed the virus to different selective pressures. And the treatment exposes infected patients to a cocktail of antibody and antiviral therapies. This puts an ‘evolutionary pressure’ on the virus to evolve and evade the immune responses. Another reason why virus is mutating is that a certain level of immunity has already developed in most populations, especially in places where cases have been widely reported. These mutations help virus to become immune-escape which means virus can save itself even if a human has antibodies. Therefore, immune system plays an important role in driving which mutations of Covid-19 survive and which are transmitted.

The combination of what the virus does and what we do determines how fast it spreads. With new variants, the situations are different because there is less room for error in controlling the spread as restrictions are relaxed and tightened, considering the lessons learnt in the past. However, at present, there is no evidence that the new variants can be kept at bay by following the same precautions, or that they can fundamentally evade masks, social distancing or other interventions. As there is no guarantee that those same preventions and cures would work, the least the governments can do is to stay vigilant and apply restrictions more strictly.

As the mutations of Covid-19 accumulate in a pandemic that is still unfolding, there is always a danger of them becoming resistant to our natural immune defenses, antibody therapies and vaccines. This leads to an inevitable question- Will these mutations make the newly approved vaccines less effective? If the virus continues to mutate at this rate, the current vaccines may ultimately prove as ineffective. As every mutation makes it look slightly more different to the immune system, this has raised fears that vaccines will need to be tweaked. We can expect that people might require repeated vaccinations in future to keep pace with mutations. 

More mutations of Covid-19 could lead to more variants before the pandemic is completely under control. The B.1.1.7 variant is beginning to mutate again and this could affect the way we handle the virus and would also undermine the protection given by current vaccines. This has already been seen when following a preliminary study and clinical trial that showed Oxford/AstraZeneca vaccines offered minimal protection against the B.1.351 coronavirus variant dominant in the country, South Africa, that temporarily halted vaccine rollouts.

Existing vaccines will work to some extent as the strains do preserve features of the original.  Even if a variant slightly diminished the efficacy of a vaccine, the shot would still confer some degree of protection. However, it is evident that the battle against COVID-19 is likely to be a long-term project. These mutations, however small they may be, will also make it harder to achieve herd immunity. At present, they are likely to have a minor impact, but in the long run, these mutations might make it difficult for the immune system to respond.

 

References:


Coronavirus variants and mutations: The science explained dated 06.01.2021
The Coronavirus Is Mutating: What We Know About the New Variants dated 22.01.2021
COVID-19 Outbreak Explained: What Is Coronavirus Mutation? dated 31.08.2020
How will Covid-19 evolve in the future? dated 20.01.2021

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