Why you should be afraid of new coronavirus variants from the UK

2020 will be remembered by the emergence of a new virus, SARS. Coronavirus 2 (SARS-CoV-2) and COVID-19 Pandemic It caused. In the next few days, 2020 is projected to end with approximately 84 million confirmed Covid-19 cases and more than 1.8 million deaths.

Despite this depression, vaccine development, testing and approval took place at an alarming rate, and this year was also a year of hope. For the first time, the pandemic of human disease will be controlled by vaccines in real time.

India has suspended all flights from the United Kingdom, increased surveillance at the airport and stopped importing highly infectious variants. (Express photo by Partha Paul)

Nobel laureate Joshua Lederberg, one of the most influential thinkers in modern biology, once said, “The only greatest threat to human continued domination on Earth is the virus.” It was. Two recent developments remind us why viruses can be such formidable enemies.

With the discovery of 58 people who tested positive for the new coronavirus in Antarctica, the pandemic spans all continents. And Mutant virus In Britain, the world could be closed again. The world is just beginning to recover from blockades and movement restrictions.

Virus mutation

The genetic material or genome of SARS-CoV-2 is ribonucleic acid (RNA) composed of over 30,000 units (called nucleotides). Coronavirus has the largest genome in the family of RNA viruses. Most other RNA viruses have an average of about 10,000 nucleotides. From the smallest virus to humans, whether DNA or RNA, the replication of the genome results in random errors (or mutations). Higher organisms have a mechanism to correct these errors, but viruses, especially RNA, do not.

Most mutations are harmful and those viruses are never seen. Only mutations that offer some selective benefits lead to the evolution of new viral variants.

Evolution also requires selective pressure. In the case of viruses, this may be the ability to infect better and multiply in higher numbers or evade the host’s immunity. The low likelihood of these events is compensated for by the high viral replication rate. For example, each cell infected with coronavirus produces about 1,000 new virus particles within 12 hours.

British mutant

A different phylogenetic cluster or strain of SARS-CoV-2 (named B.1.1.7) was recently discovered in the United Kingdom. The two earliest viruses of this strain were collected from Kent and Greater London on September 20 and 21, respectively. By December 15, this strain contained 1,623 viruses. 555 from Kent, 519 from Greater London, 545 in other parts of the UK including Scotland and Wales, four from Australia, Denmark, Italy and the Netherlands.

After the coronavirus outbreak in London, England, on December 21, 2020, travelers look at the information board at King’s Cross Station as EU countries impose a ban on travel from the United Kingdom. (Reuters / File)

In another 10 days (December 25th), the number of these variant viruses more than doubled to 3,575. Mainly from the UK, but now also from France, Ireland, Israel, Hong Kong and Singapore. ? Express description Currently on telegram..click Join the channel here (@ieexplained) Get the latest information

What does a mutation do

Compared to the original SARS-CoV-2 strain, this strain of virus has accumulated 23 mutations across 5 genes. Of these, there are 17 non-synonymous mutations and 6 synonymous mutations. The former also modifies the amino acids at that site of the protein. Importantly, eight of the 17 non-synonymous mutations are in peplomers, proteins that allow viruses to attach to and invade cells.

The N501Y mutation, which is one of the key contact residues in the receptor binding domain (RBD) of peplomer proteins, enhances its affinity for the ACE2 receptor. The P681H mutation at the cleavage site between the S1 and S2 domains of the spike protein promotes entry into susceptible cells and increases infection in animal models of infection.

Changes in N501Y are also associated with increased infectivity and pathogenicity in animal models. Both of these mutations were previously observed independently, but have been combined in the UK variant virus. The result is a virus that spreads faster than before.

Cause of worry …

There is growing concern that these mutations may make the virus undetectable by currently used tests, make the virus more deadly, or evade vaccines under development. There is no evidence so far for any of these. After all, these mutants were found in people identified as positive by the RT-PCR tests currently available.

However, while there is no evidence of a more serious disease, there is clear evidence that this mutant is more contagious. Infected people produce more virus in their nose and throat, which leads to more viral shedding and person-to-person transmission.

These variants appear to be less deadly, but the more infected, the higher the number of severe infections and deaths (not percentages). This should be a source of concern.

… and why not

Spike proteins have multiple mutations, but most experts believe that the vaccine currently under development will also work on mutant viruses. Vineet Menachery, an assistant professor of microbiology and immunology at the University of Texas School of Medicine in Galveston, USA, provided the first evidence for this.

In his laboratory, collected serum samples from Covid-19 patients were compared to neutralize the virus with or without the N501Y mutation. They didn’t find a difference. Although only shared on Twitter on December 23rd and not yet part of the publication, these results are encouraging and encouraging.

Takeoff, not mutation

India has suspended all flights from the United Kingdom, increased surveillance at the airport and stopped importing highly infectious variants. At first glance it may seem like a rational strategy, but such variants are easy to develop domestically. After all, more than 10 million infections have been confirmed in India, and it is estimated that 150 to 200 million people are already infected.

A couple crossing the road with an umbrella and shopping bags at Mayfair prior to the new Tier 4 restrictions in London on Saturday, December 19, 2020. (AP photo / file)

A fast spreader variant called 501.V2 has emerged independently in South Africa and shares the N501Y mutation with the UK variant. The spike N501Y mutant has not yet been found in India, but a virus with the P681H mutation began to emerge in July, and 14% of SARS-CoV-2 currently prevalent in India carry this mutation. I will.

These viruses are primarily from Maharashtra, and some from West Bengal. To know where Britain is today, we need another mutation. And that should also worry us in India.

Prompt response is the key

The World Health Organization (WHO) has decided to sequence the viral genome from at least one (or 0.33%) of every 300 confirmed cases to capture the emergence of new viral variants before they become widespread in the population. Recommended. The United Kingdom has sequenced 135,572 or 6.2% of viral variants from 2.19 million cases, while South Africa and the United States have reported genomic sequences from 0.3% of confirmed cases.

However, India has so far sequenced only 4,976 or 0.05% of the viruses from over 10 million cases. At this rate, the emergence of new variants remains unnoticed until it’s too late. One of the basic elements of disease monitoring is proper coverage and density to catch an event before it becomes widespread.

India’s conditions to promote

Another reason to worry is that there are conditions in India that are supposed to produce British variants. Patients with immunodeficiency or immunosuppression who are chronically infected with SARS-CoV-2 remain viral RNA positive for 2-4 months instead of the usual 2-3 weeks. These patients are often treated with convalescent plasma (sometimes more than once) and are usually treated with a drug called remdesivir.

Viral genome sequencing from such patients revealed an unusually large number of nucleotide changes. It is also known that the genetic diversity of the virus in patients increases after plasma therapy. Poor nutrition is a known cause of weakened immunity, and Indian doctors have reported chronic infections in some patients.

Some unknowns remain

Plasma therapy and remdesivir are also widely used to treat Covid-19 patients in India. In addition, plasma is administered in India without first testing the levels of neutralizing antibodies. All of these create opportunities for British variants to emerge in India as well. But there isn’t enough sequence to know if that happened.

Even with low coverage, sequences from India are biased in urban areas, especially in metros where sequence labs are located. This requires a wider range to include all regions of the country. The Indian Medical Research Council can facilitate this process by providing access to samples from Covid-19 patients to laboratories with genomic sequencing and data analysis capabilities. Real-time monitoring provides high-density, detailed data for setting evidence-based policies.

Advance with “SMS”

The wider the vaccine, the greater the selective pressure on the virus. Vaccine escape mutants are well known in other viruses and also appear in SARS-CoV2. Only proper genetic monitoring can successfully capture vaccine failure in time.

Entering 2021, the message to policy makers and the general public will be clear. Public health overseers must continually seek fresh evidence to formulate policies at the population level. At the individual level, each of us needs to work to reduce virus infection. Fewer infections mean less chance of the virus changing. And SMS is the only tool we have at the moment — Avoid crowds, Mask and disinfection.