The second wave of Covid-19 has been considered to be more dangerous. There are many queries about the second wave. Regarding this matter, Dr. Samiran Panda, Head- Division of Epidemiology and Communicable Diseases, Indian Council of Medical Research (ICMR), Ansari Nagar, New Delhi and Director, National Aid Research Institute (NARI) spoke to BE's Kishore Kumar Biswas.
Q. What causes the virus to change to a new variant?
A. Viruses at the time of proliferation go through the process of replication of their own genetic material. Such replication of genetic material is prone to error (particularly when speed of replication is high) as we see errors happening while copying an original narrative text to a notebook. However, at the time of reading the copied text before finalisation, we make corrections while we identify an error you may wish to call this process - corrections through proof reading - before we say we are done with copying or creating a replica of the original. Viruses that lack a proof reading system end up creating replica, which are with errors. These generations of viruses with errors are called mutant versions of the virus or in short mutants. May be one amino acid gets replaced by another amino acid in the resultant mutant or at times, the mutant version of the viruses may have part of the genetic material missing or deleted. The immunological pressure from the host (humans, animals or plants) sometime forces such mutations to occur in the viruses residing in the host. Mutations may or may not offer survival advantage to the viruses.
A variant of a virus may have single point mutation or multiple mutations. The viral variants are studied in the laboratory for their potential to infect host cells more efficiently or for their ability to evade the detection system developed for diagnosis or their ability to evade the effect of vaccines. Till this stage the variants are termed as variants of interest (VOI). However, when a particular variant of a virus is identified as responsible for rapid transmission of infection in a community or greater severity of disease based on epidemiological or clinical evidence, the variant is termed as a variant of concern (VOC).
Q. It is said that India is battling with the double mutant coronavirus mutation. What does it mean?
A. While two distinct mutations are encountered in a virus, the mutant is termed a double-mutant and the one such mutant which is being discussed with regard to India and Covid-19 is being examined for its ability to cause outbreaks and/or severe clinical disease. As with other mutations, the changes identified in double-mutant version of a virus are studied for their effects at cellular level in the laboratory. In order to identify the effects of these mutants at population level, epidemiologic surveillance is also being undertaken in the community. India, as many other countries, are mapping and cataloguing mutations in SARS-CoV-2 virus that is circulating in the country. It is important to appreciate at this point that associating name of any country with a mutant is not a good idea and such a practice could be stigmatising. Following a systematic and objective approach to designate newly emerging viral variants based on their lineage and evolution over a period of time would rather be scientific.
Q. Are the new variants more dangerous? Why?
A. Not every emerging viral variant turns out to be dangerous or deadlier. In fact, a virus gains survival advantage only when its mutant version is able to spread faster because increased transmissibility will mean greater chance of encounters for the newly generated viral particles with new host cells, which serve as the kitchen on which the viruses grow and proliferate. A deadlier mutant version of a virus, by killing its host, will reduce the chance for newly developed viral particles to find new host cells in which they can survive and proliferate. It is important to appreciate at this point that the viruses cannot survive independently. They require living cells (of animals, humans or of plants) to survive and proliferate and some mechanism such as coughing, talking or sneezing (in case of SARS-CoV-2) to move from one host to another. As face mask when properly worn - breaks this chain of transmission,
Q. Should people get vaccinated even if there are new variants of the covid virus?
Or will the existing vaccines be effective for the new wave of Covid-19?
A. Yes, people should get themselves vaccinated although information on new variants of SARS-CoV-2 circulating in India is making its rounds in different media because the vaccines are effective against many new variants .
Q. Some countries have been taking protectionist policy about supplying covid vaccines. Will not it affect many developing countries in fighting against the Covid-19? What can be a way out?
A. Diseases do not require passport and organisms do not respect borders. The way forward therefore is clearly considering the whole world as one family and joining hands with each other. Certainly, vaccine nationalism cannot be the way forward as diseases in todays world of great connectivity through air, land and water, do not remain restricted to any particular nation.