Not every virus mutation is issue of concern, say experts
NEW DELHI: Has Sars-CoV2, the virus that causes coronavirus disease, mutated to become more lethal and contagious? Researchers around the world have identified dozens of mutations that they said has made the virus more deadly or transmissible, or both, which has fuelled uncertainty, but some experts say there is no significant mutation to suggest change in viral behaviour.
Researchers at the Los Alamos National Laboratory in the US recently said they had identified 14 mutations, of which “the mutation Spike D614G is of urgent concern; after beginning to spread in Europe in early February, when introduced to new regions it repeatedly and rapidly becomes the dominant form”. The study, published in pre-print server, bioRxiv, on April 29, has not been peer-reviewed.
But several experts argue that these findings have no clinical significance. A virus causes infection by entering the host cell
RESEARCHERS AT THE LOS ALAMOS NATIONAL LABORATORY IN THE US RECENTLY CAUSED ALARM WHEN THEY IDENTIFIED 14 MUTATIONS
and making copies of itself, which it does by duplicating its genes. Small errors in the duplication become mutations, which usually have no effect on viral behaviour. “It is normal for viruses to change over time and to become more or less transmissible, cause more or less fatalities. The virus causing Covid-19 disease remains relatively stable so far,” said Dr Poonam Khetrapal Singh, regional director, World Health Organization, South-East Asia region, of which India is apart.
Not every mutation creates a new strain, which is used to describe a lineage that is significantly different from earlier viruses. “In my opinion, there is no clear evidence of any different strains of clinical significance. By sequence, one can identify phylogenetic clades, some of which show mutations of possible significance...,” said Dr Anurag Agrawal, director, Council of Scientific & Industrial Research-Institute of Genomics and Integrative Biology (CSIR-IGIB), New Delhi. CSIR-IGIB, along with the National Centre for Disease Control in Delhi submitted 53 sequences of genomes to Global Initiative on Sharing All Influenza Data, which is the largest submission by any group in India.
“All viruses mutate all the time, there’s no significant mutation,” said Dr Soumya Swaminathan, chief scientist, WHO.
“Mutations in themselves are not a bad thing and there is nothing to suggest Sars-CoV-2 is mutating faster or slower than expected. So far we cannot say whether Sars-CoV-2 is becoming more or less lethal and contagious,” said Professor Francois Balloux, from University College London Genetics Institute, UK, and co-lead author of a study that identified 198 recurring mutations to the virus, in a statement.