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'UK variant may carry higher risk of death'
There is some evidence that a new coronavirus variant first identified in southeast England carries a higher risk of death than the original strain, the British government's chief scientific adviser said on Friday as scientists around the world investigate how and why the virus became more transmissible.
Patrick Vallance told a news conference that "there is evidence that there is an increased risk for those who have the new variant" but stressed that the data was uncertain.
He said that for a man in his 60s with the original version of the virus, "the average risk is that for 1,000 people who got infected, roughly 10 would be expected to unfortunately die."
"With the new variant, for 1,000 people infected, roughly 13 or 14 people might be expected to die," he said.
But Vallance stressed that "the evidence is not yet strong," and more research is needed.
In contrast to that uncertainty, Vallance said, there is growing confidence that the variant is more easily passed on than the original coronavirus strain. He said it appears to be between 30 percent and 70 percent more transmissible.
Maria Van Kerkhove, the World Health Organization's technical lead on the coronavirus disease-19 (Covid-19), said studies were underway to look at the transmission and severity of new virus variants.
Kerkhove said so far "they haven't seen an increase in severity" but that more transmission could lead to "an overburdened health care system" and thus more deaths.
More infectious strains
The emergence of several, more infectious strains of the novel coronavirus SARS-CoV-2 has worried governments and scientists, who are investigating how and why the virus became more transmissible.
Like all viruses, SARS-CoV-2 mutates in order to maximize its survival chances.
When it replicates, tiny errors in its genetic coding are introduced.
Most of these are inconsequential. But some -- as with the virus variants that emerged recently in Britain, South Africa and Brazil -- can give the virus a decisive new advantage.
"When we keep case numbers high, we are maximizing the virus' opportunities to get into weird situations, that might be rare, and most of them might lead nowhere," said Emma Hodcroft, epidemiologist at the University of Bern.
More cases equal more transmissions, which maximizes the chances that a significant mutation will occur, she said.
"If we keep case numbers lower, we essentially restrict the virus' playground."
Wendy Barclay, a virologist at London's Imperial College, said mutations were, among others, "a combination of how much virus is out there, the number of times you roll the dice defines what happens, coupled with the environment the virus is currently in."
It was not unexpected for the new variants to appear after a year of Covid-19 as levels of global immunity increase through vaccinations and natural infection, she added.
"In South Africa and Brazil there was already quite a high level of antibody response from people who had been infected and recovered from the virus."
The evidence for the new variant being more deadly is in a paper prepared by a group of scientists that advises the government on new respiratory viruses, based on several studies.
British scientists said that although initial analyses suggested that the strain, first identified in September, did not cause more severe disease, several more recent ones suggest it might. However, the numbers of deaths are relatively small, and case fatality rates are affected by many things, including the care patients get and their age and health beyond having Covid-19.
The British scientists stress that the information so far has major limitations, and that they do not know how representative the cases included in the analyses are of what's happening throughout the country or elsewhere.
Immune issues may also have impacted the virus in another way.
France's Academy of Medicine says that the South African variant "could result from a viral replication more intense and prolonged in people living with HIV" -- cases of which are highly prevalent there.
While the precise origins of the variants remain up for debate, scientists are unanimous that their effect needs careful management.
One thing is for sure: the virus will continue to mutate, which might bring more dangerous variants.
In fact, they may already be circulating.
"And because the total number of cases continues to grow exponentially, it is not hard to argue that more variants of concern arose this winter and remain undetected than arose in fall and now are on our radar," University of Washington biologist Carl Bergstrom, wrote on Twitter.
"I don't think this virus is going anywhere," Vallance said. "It's going to be around, probably, forever."
[Source: The Manila Times, Ap an Afp, Manila, 24Jan21]
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