By: Adelle Fernandes
In recent times, India became the latest country to shut its borders to the United Kingdom when a full lockdown was imposed in London and Southeast England to control the spread of a mutation of the Coronavirus. It is not surprising that a mutation exists, as viruses mutate. However, what is surprising and alarming is the rapid spread of the new mutation of the Coronavirus that originated in UK.
About UK’s mutation
Compared to the original SARS-CoV-2 strains, viruses of this lineage have accumulated 23 mutations across 5 genes. Of these, there are 17 non-synonymous and six synonymous mutations; the former also change an amino acid at that site in the protein. Importantly, of the 17 non-synonymous mutations, eight are in the spike protein, that allows the virus to attach to and enter cells of the body.
The N501Y mutation in one of the key contact residues in the receptor binding domain (RBD) of the spike protein increases its affinity for the ACE2 receptor. The P681H mutation in the cleavage site between the S1 and S2 domains of the spike protein promotes entry into susceptible cells, and increases transmission. The N501Y change is also associated with increased infectivity and virulence in animal models. Both these mutations were observed earlier as well, but they existed independent of each other. However, they have come together in the UK variant viruses and this has resulted in a virus that spreads faster than before.
Why Fear the Mutation?
This new mutation of the Coronavirus has sparked fear in many. What adds to this fear is the fact that the mutation may prevent currently used tests from detecting the virus, make it more lethal, or allow it to sabotage the efforts of vaccine developers. There is no evidence so far for any of these, as the variant was found in people who were identified to be positive with currently available RT-PCR tests.
However, there is evidence that proves this mutation to be more contagious and present in the nose and throat. Researchers have also stated that the rapid spread of the mutation of the virus can be attributed to more virus shedding in those affected by it. This means that as the number of those infected by the mutant virus increases, the chance of others getting infected also increases, thus making it a deadly mutation.
India and the UK mutation
Apart from population and lack of hygienic living conditions, the conditions assumed to give rise to the UK variant are present in India as well. Immunodeficient or immunosuppressed patients, who become chronically infected with SARS-CoV-2, remain positive for viral RNA for 2-4 months instead of the usual 2-3 weeks. These patients are often treated with convalescent plasma and usually prescribed the Remdesivir drug. Virus genome sequencing from these patients has revealed alarmingly large numbers of nucleotide changes. Intra-patient virus genetic diversity is also known to increase following plasma therapy. Poor nutritional status is a known cause for weak immune systems and physicians in India have reported chronic infection in a subset of patients.
A Ray of Hope
A number of experts believe that the vaccines that have been developed and administered to a few in certain countries will shield people from catching the mutant coronavirus. As per a report in the Indian Express, Vineet Menachery, an assistant professor of microbiology and immunology at the University of Texas Medical Branch in Galveston, compared the efficacy of serum samples from recovered Covid-19 patients to neutralize viruses with or without the N501Y mutation. He and his team found no difference. This is definitely a ray of hope and is encouraging and reassuring information. It is true that much about the virus and its mutation still remains unknown. However, it is up to each citizen to take responsibility and wear a mask, sanitize and ensure social distancing norms are followed.
2. India Today