Coronavirus: No sign virus will mutate to become more deadly, experts say

‘I don't think this virus is so unusual that it's going to wipe us out, or make us have to live in the peculiar way we're living at the moment’

There are no signs that coronavirus will mutate to become more deadly, scientists have said, adding that the pathogen will eventually fade into the background - similar to other viruses that are in circulation throughout the global population.

Although it's largely expected that Sars-CoV-2, the virus responsible for Covid-19, will become endemic, there is hope that the impact of the disease will lessen as immunity within communities is slowly built up, the experts said during a media briefing.

Paul Lehner, a professor of immunology and medicine at the University of Cambridge, said that with time people will either be vaccinated or have exposure to Sars-CoV-2 as a child, offering them a degree of protection that would help to maintain the virus at a baseline level within the population - like chickenpox.

He admitted he was taking a "positive viewpoint", saying it was still not known what course the pandemic will take, but insisted there was cause for optimism.

"I don't think this virus is so unusual that it's going to wipe us out, or make us have to live in the peculiar way we're living at the moment," Prof Lehner said.

“I'm going to take a positive viewpoint and say, I think it's going to become similar to the four circulating endemic coronaviruses [which cause the common cold in humans].

“You're going to either get vaccinated, or you're going to catch it when you're young and young people do not get sick with this virus.

“People will be invited to parties – like chickenpox parties – so you don’t get it when you’re older, but we’ll have to wait and see.”

He said that natural protection against Covid-19 may wane, highlighting that people are regularly reinfected with other coronaviruses responsible for the common cold, but insisted  that "background immunity" would reduce the severity of any illness that develops.

"I think this is something we have to keep an eye on, we have to worry about," he said. "But I think we have to be optimistic and say that this is the sort of thing our immune system has developed to deal with, and it will deal with this virus.

"It's just these extraordinary circumstances because it's a brand new virus."

Prof Lehner added that although the virus has "proof-reading capabilities", meaning it has the capacity to mutate, it's unlikely this is "going to be a major problem".

Mauro Giacca, professor of cardiovascular sciences at King's College London, said there was no evidence that pathogenic coronaviruses such as Sars-CoV-2, Mers or Sars were capable of adapting to the human population.

"We have now tens of thousands of sequences from the virus worldwide, and there is no sign of adaptation or mutation that could render it more prone to establish a latent and persistent infection."

Prof Giacca said he was optimistic that the "virus would disappear", in the same way that both Mers and Sars have dropped out of circulation within humans.

He also pointed to the example of Spanish Flu, which devastated the world population in a series of waves from 1918 to 1920 before eventually dying out. By 1957, it had "completely disappeared".

"So we have to be patient with this one," Prof Giacca said, adding that it could be a number of years before Covid-19 fades away.

Professor Tracy Hussell, director of the Manchester Collaborative Centre for Inflammation Research at the University of Manchester, said that humanity had also come to live with swine flu - which is estimated to have infected millions between 2009 and 2010.

"We got used to that [swine flu]. It's still around but it doesn't cause quite as much devastation as it did," she said. "So it's almost like we get over the shock of the thing."

Prof Hussell said there was reason to believe that Covid-19 will become "a little bit milder" for the general population in the years to come, apart from in vulnerable groups.

The experts also discussed the uniqueness of Sars-CoV-2, and what sets it apart from other viruses that cause diseases within humans.

"One thing about this virus is it's transmissibility," said Prof Hussell. "And the fact we've not seen this form of virus before. When you start to mix viral strains from alternative species they can have quite a shock on your immune system."

Prof Leaner said the virus had evolved to "switch off our early warning system" and was as its most infective prior to the onset of illness.

"This virus is brilliant," he said. "You're feeling completely well [when infectious]. So you don't go out, you have a good time and spread it. It's evolved to do that."