A new strain of Sars-CoV-2, the virus that causes Covid-19, is reported to have been found in parts of England and it is growing. United Kingdom’s Health Secretary Matt Hancock said that at least 60 different local authorities have recorded infection caused by the new strain. He also said that over 1,000 cases have so far been identified with the new variant of the virus predominantly in the South England.
The World Health Organization (WHO) has also been notified about it and it is under consideration. Dr. Michael Ryan, the executive director of WHO Health Emergencies Programme, was quoted to have said to The Guardian— “This kind of evolution and mutations are actually quite common. The question, as we’ve had most recently with the mink variants in Denmark and previous variations, is: does this make the virus more serious? Does it allow the virus to transmit more easily? Does it in any way interfere with diagnostics? Would it in any way interfere with vaccine effectiveness? None of these questions are addressed yet.”
Mutations are very common in viruses. In fact, it is the primary driving force of evolution. These small changes in a viral genome are random and happen in the process of replication of the genetic material. Often these mutations don’t have a significant effect on the functioning and survivability of the virus. However, in some instances, mutations can render a virus to become deadlier by making it more contagious, and in others, mutations can hamper the virus by making its survival difficult. This effect of mutations makes it important to study them to track the progression of a viral disease.
The mutations that don’t make any visible change on the part of a virus’s dynamics are nothing to be worried about and these do not give rise to a new variant or a strain. To become a new strain--a variant of the same species with different characteristics--a virus has to undergo mutations that bring in visible changes in it. For example, for a particular virus, if some mutations make a population of the virus more contagious than others, then we would consider it as a different strain in comparison to the other populations of the virus, which are not so contagious. In this way, a virus can express in various strains during the course of its evolution with mutations as the driving force.
The SARS-CoV-2 virus has also changed itself from where it started a year ago in China and the basis is mutations. However, this virus has a slow rate of mutation and a previous study has shown that the D614G strain is the most dominant one worldwide. Other studies also reported to have detected this strain in several places. This strain has been thought to have a greater infectivity, but lesser disease severity. However, conclusive results are yet to come out.
Concerns Over New Strain
Though not much is known yet, the new strain of the virus detected in England can have many probabilities. One is that it can spread more easily and thus, can cause more infections. The strain’s presence is also higher in places where infection cases are higher. The mutations that this particular strain has are in the spike protein, the agent through which the virus can make an entry to our cells. The spike protein has a receptor-binding domain (a portion in the protein) that binds to the ACE2 receptors present in our cells. The England strain also has mutations in this portion of the spike protein.
To become more contagious, the spike protein mutations had to have cause a change in the protein so that the bonding to the host cell becomes much easier. More laboratory evidences will be required to say anything definitively regarding the contagiousness of the England strain.
The other important concern is that whether vaccination become ineffective for the people infected by the new strain. This is because, in most of the vaccines, the target is the spike protein of the novel coronavirus. Health officials, however, still believe that vaccines would work against the variant because the body knows how to unleash attacks on different parts of the spike protein.
It is important to track the virus evolution so as to upgrade the vaccines in future accordingly, as is done in case of flu for example.