“Right now, there is good evidence to show that when someone becomes infected with COVID-19, they typically shed virus for about 10 days. That's why the CDC asks people to isolate for 10 days after a positive test.
“But if these variant viruses mutate to prolong this period, 'they are shedding virus sooner and transmitting later, increasing the number of days [of being contagious],' Dr. Angela Rasmussen, a virologist and associate research scientist at the Center for Infection and Immunity at Columbia University's School of Public Health, said.
“That could cause others to be infected, because you might not be quarantining when you should be and therefore exposing others unknowingly.”
– Dr. Sean Llewellyn, ABC News
Mutation is an inevitable consequence of being a virus – it is “normal and expected” according to Dr. Richard Kuhn – director of the Purdue Institute of Inflammation, Immunology and Infectious Disease and editor-in-chief of the journal Virology. It should not be exaggerated and not cause unnecessary fear.
Most of us remember the 1995 thriller Outbreak, in which a fictional Ebola-like virus rapidly mutates into a highly infectious strain capable of aerosolized transmission. Journalists and scientists are sometimes predisposed to draw upon these fictional views.
Mutations can result in a new “lineage” of the virus. This is not the same as a new strain. Tracking these lineages can be very useful for determining how a virus spread through communities or populations.
In recent months, new variants of the virus that cause COVID-19 have been popping up all over the world, and experts say even more will continue to be identified as this pandemic continues.
In the United States, variants have been found in California and the Midwest in recent weeks, and last month, new variants from the U.K., South Africa and Brazil were identified. There is strong evidence that two of the variants -- those that were first identified in the U.K. and South Africa -- are more transmissible. Now, scientists are racing to understand why.
(Sean Llewellyn. “Some COVID-19 variants spread more easily than original: Here’s why.” ABC News. January 22, 2021.)
These changes are random and most are unimportant, but each infection increases the risk of a mutation that could make the virus more infectious, deadlier, or just different enough to render vaccines and natural infections less protective, or treatments ineffective, said Dr. Robert Bollinger, a professor of infectious diseases at Johns Hopkins School of Medicine.
(Karen Weintraub and Elizabeth Weise. “New strains of COVID swiftly moving through the US need careful watch, scientists say.” USA Today. January 22, 2021.)
On January 22, Prime Minister Boris Johnson suggested there was early evidence suggesting that the UK, or Kent, variant may be more deadly, although government scientists stressed that the data so far is uncertain. Here's what we know so far.
Paul Nuki, Global Health Security Editor in London, reported that there is good evidence that the UK strain is more transmissible and some evidence the other two may be too.
The government’s chief scientific officer, Sir Patrick Vallance, suggested it might increase the case fatality rate (CFR) by 30 percent. To put this in context, he said that out of 1,000 men in their 60s infected with the old variant, 10 would be expected to die, compared to 13 with the new variant..
Nuki said: “The maths of contagion is counter intuitive. A virus which is 50 per cent more transmissible will kill far more people than one which is 50 per cent more deadly as it infects so many more people.”
(Paul Nuki; Anne Gulland; Jennifer Rigby and Sarah Newey. “Covid-19 variants: Are new mutations more deadly, and will vaccines work against them?” The Telegraph. January 23, 2021.)
Theories about what leads the virus to being more transmissible (leaving one body in search for another) include the following:
1. Increased virus shedding
People who are infected with the variant could be shedding more virus through droplets of mucus and saliva in the air. Preliminary data from the U.K. suggests people infected with the new variant tended to have higher viral loads -- meaning they had more volume of virus in their noses, which could be measured using a nasal swab.
2. Prolonged virus shedding
In a related theory, scientists are investigating whether the new variant might somehow lengthen the number of days an infected person is contagious.
3. Increased environmental stability
Yet another idea – with no scientific evidence yet -- is that the virus might have evolved to be sturdier and better able to withstand the harsh environment outside the human body. This allows it to remain in the air or on surfaces for longer periods of time and remain infectious, making transmission from person to person easier. The common cold has done this.
4. Better able to "stick" to cells
One of the leading theories that has the most evidence behind it is the idea that the new, more transmissible COVID-19 variants are simply better at latching onto our cells. (However, it could be any one of these theories, and it could be a combination of them.)
ABC News reports that many scientists feel confident about this theory because the mutations they found in the U.K. and South African variants are in those little "spikes" on the outside of the virus. The virus uses those spikes to bind to a specific site on our cells called the ACE2 receptor.
(Sean Llewellyn. “Some COVID-19 variants spread more easily than original: Here’s why.” ABC News. January 22, 2021.)
Most experts think vaccines will still be effective, at least in the short term.
Dr. Julian W Tang, a virologist at the University of Leicester, says vaccines can be modified to be "more close-fitting and effective against this variant in a few months.” Tang says …
"Meanwhile, most of us believe that the existing vaccines are likely to work to some extent to reduce infection/ transmission rates and severe disease against both the UK and South African variants – as the various mutations have not altered the S protein shape that the current vaccine-induced antibodies will not bind at all."
(Helen Briggs. “Coronavirus variants and mutations: The science explained.” BBC News. January 06, 2021.)
And here in the U.S.? California Governor Gavin Newsom announced December 30 that the new strain, known as B.1.1.7 (the UK variant) was detected in the southern part of the state. It’s the second report of the UK variant in the US in as many days, following news that the variant was found in a male Colorado National Guard member in his 20s with no history of travel, a sign that the virus is spreading locally.
(Brian Resnick and Umair Irfan. “The new UK coronavirus mutations, explained.” Vox. Decembeer 30, 2020,)
UC San Francisco infectious disease expert Charles Chiu, MD, PhD, whose lab has been helping the state of California detect cases of the new variant, says …
“The virus is already very infectious at baseline, so I think the effectiveness of the public health response and individual responsibility to prevent spread has much more impact than a small degree of increased transmissibility.”
“The important thing is not necessarily to focus on the variants, but to focus on the virus overall – limiting the number of cases by controlling transmission and deploying the vaccine so that we can reach herd immunity” said Chiu.
(Nina Bai. “How Worried Should You Be About the New Coronavirus Variant?” University of California San Francisco. January 12, 2021.)
The virus is mutating. Is this mutation a major factor in the virus’s evolution? Time will tell, but the population must continue to take safeguards against infections – any infection, new or old. It is imperative that we watch the changes in the virus to defeat COVID-19. Of course, a speedy vaccine rollout would be helpful in stopping the mutations from developing so quickly.
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