Updated: May 6, 2021 7:09:23 am
The Principal Scientific Advisor to the Prime Minister Wednesday said a third wave of Covid-19 was inevitable given the high levels of the circulating virus and that they couldn’t predict a time frame for it. Dr K V VijayRaghavan also admitted that experts had not anticipated the “ferocity” of the second wave currently sweeping the country.
The PSA said the new variants now affecting people are “fitter”, had adopted a “hit and run lifestyle”, and required a new approach.
Addressing a briefing of the Union Health Ministry, VijayRaghavan said, “Phase 3 is inevitable given the high levels of circulating virus. But it is not clear on what timescale this Phase 3 will occur. Hopefully, incrementally, but we should prepare for new waves.”
He also said previous infections and vaccines could cause the coronavirus to further mutate in order to survive. “Therefore, we should be prepared scientifically to take care of that.’
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About the reasons behind the second surge, the PSA said both the fact that the immunity from the first wave was not widespread and lowering of guard were responsible. “In early 2021, something changed rather importantly. A very large number of people, all over the world, had been infected, and as immunity increases, a virus can’t spread. But, it seems, there are pockets it can go through.”
He said they also believe the virus has become more efficient in transmission, and the health authorities needed to take that into account. “The changes in biology that we are seeing, along with the increased transmission… suggest a new approach. Earlier, the virus infected people, they were largely asymptomatic, and it had a certain profile of progression. Now, because of fewer (uninfected) people available, it has adopted a hit and run lifestyle.”
VijayRaghavan characterised these new variants as “fitter” viruses, capable of breaking through increased host immunity. He said as the virus adapts more, it could increase or decrease disease severity, but the rate of transmission will likely slow down. “Vaccines are effective against the current variants, new variants will arise all over the world. But variants which increase transmission will likely plateau; immune-evasive variants, and those which lower or increase disease severity, will arise,” he said.
About what took them by surprise about the second wave, VijayRaghavan said lowering of guard gave the virus an opportunity to spread. “The standing level of immunity is often not enough to stop the infection from spreading, and many people get infected until we reach a new immunity threshold. Such a second wave is typically smaller than the first, and such a second wave was expected. However, multiple parameters can change in small amounts and add up to a second wave much larger than the first. Each parameter may seem like a small change, but together, because the rise is exponential, it adds up enormously.”
He said the huge surge also showed that immunity from the first wave was not widespread. “The fraction uninfected, due to the cautionary steps taken in the first wave (lockdowns etc), had been large.”
However, VijayRaghavan said, their findings suggested that once infected, immunity can last for a long time. “We know that after eight months of being infected, protection is still very high. It is about 80%;” he said, adding, “But could 20% be sufficient to cause immune evasion of significance?”
Asked specifically at the briefing if the government was looking at the option of a national lockdown, as being recommended by some, Dr V K Paul, who heads India’s Covid-19 task force, said, “Those options are always being discussed. Those decisions as required will be taken.”
Paul said, “When the spread of the virus is excessive, then movement needs to be reduced. In this context, on April 29, detailed guidelines were issued, specifically that where test positivity is more than 10% or bed occupancy is more than 60%, states have been advised on (imposing) night curfews here… Based on these advisories, states are deciding. In addition to these restrictions, if anything more is required, those options are being discussed.”
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