As scientists search for ways to predict the virus’s next moves, here are more insights about its mutation, classification, future scenarios and how they can be stopped from mutating.
The world has stepped into the third year of the coronavirus pandemic and it is still not clear if this is the end or new variants more transmissible and virulent are evolving to bring another wave and newer challenges for health authorities. In the last two years at least 5 variants have evolved and chances of it evolving again are not few.
According to evolutionary biologist Jesse Bloom. Variants like Omicron and Delta blunt the potency of antibodies raised against past versions of SARS-CoV-2 and as more and more people get immunity to the virus through infection, vaccination or both, forces propelling the ‘antigenic changes’ are likely to grow stronger.
As scientists search for ways to predict the virus’s next moves, here are more insights about its mutation, classification, future scenarios and how they can be stopped from mutating.
How Covid strains mutate and are classified
Once virus enters a human body, its genetic material DNA and RNA start making copies inside the cells to infect other cells. Whenever an error occurs it triggers a mutation. When the virus is widely circulating, the more are its chances of replicating and mutating.
According to the US government SARS-CoV-2 Interagency Group (SIG), Covid-19 mutations of significance can be divided into three types, variants of Interest, Variants of High Consequence and Variants of Concern.
WHO also classifies significant mutant strains as Variants of Concern (VOC) and Variants of Interest (VOI) and there are four VOCs as of now — Alpha (B.1.1.7), Beta (B.1.251), Gamma (P.1) and Delta (B.1.617.2).
Mutations which involve significant changes in the spike protein can be of concern because they trigger transformations in the structure and the biochemical property of the virus.
Next SARS-Cov-2 Variant of concern – four possible scenarios
A recent article by Nature says that scientists are investigating how quickly a population will become newly susceptible to infection and whether that happens mostly through waning immune responses, new birth without immunity to the virus or viral evolution and divided findings into four possible scenarios.
In the first Scenario , the virus will circulate largely on the basis of new births. This is the most hopeful scenario where infection and vaccination or both will provide lifetime protection.
In the second Scenario the Sars-Cov-2 will follow the path of a respiratory syncytial virus in which most people get infected in the first two years of life . It can lead to hospitalisation among infants but most childhood cases are mild.
In the third scenario according to Nature, coronavirus will act like influenza A that drives global seasonal influenza epidemics , propelled largely by spread in adults and flu jabs will reduce its severity. Due to vast spread and rapid evolution the new variants will be formed that will evade immunity elicited by past strains. But this scenario will also mean vaccines aren’t always best matched.
The fourth scenario will occur if SARS-CoV-2 evades immunity sluggishly. With the virus’s slower rate of change its transmission will be driven largely by infection among children who have less immunity than adults.
The pace of the evolution of the virus will determine how often vaccines should be updated. While some evolutionary biologists expect SARS-CoV-2 will eventually slow down to a steadier state of change, other experts believe that with in-equitable distribution of vaccine , sky high circulation of variants will offer SARS-CoV-2 a fertile ground to take additional surprising evolutionary leaps.
What WHO has said about the next variant?
WHO maintains that SARS-COV-2 will continue to evolve as long as it continues to spread. The more that the virus spreads, the more pressure there is for the virus to change.
Recently a WHO official pointed out that the upcoming variant of concern will be more transmissible to overtake what is currently circulating in the population, but the big question is if it will be more severe or milder. Though theories are brewing that it will be milder than the previous variant, there is no guarantee to that.
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