Scientists say they have identified a mutation in coronavirus which they believe means a more contagious strain has been sweeping Europe and the US – and could even reinfect those who already have antibodies.
Researchers at Los Alamos National Laboratory in the US detected 14 mutations in the COVID-19 virus spike proteins, one of which – known as Spike D614G – they said was of “urgent concern”.
Their research paper suggests the mutated strain of coronavirus that has become dominant across the world was first indentified in Europe and is different to those which spread early on in the pandemic.
So urgent is the issue that the research paper describing their findings has been made available before being peer-reviewed, although this has caused concern among some observers.
By analysing more than 6,000 genetic sequences of coronavirus samples taken from patients globally, the researchers found the mutated strain was persistently becoming the most dominant version of the virus in every region it was detected in.
While first discovered in Europe in early February, the researchers believe the coronavirus mutation has now become the most prevalent strain across the whole of the world.
The study indicates it has been consistently out-competing the original strain detected in Wuhan, which spread through that region of China and some other Asian countries before March.
Dr Bette Korber, the study’s lead author, said: “The story is worrying, as we see a mutated form of the virus very rapidly emerging, and over the month of March becoming the dominant pandemic form.
“When viruses with this mutation enter a population, they rapidly begin to take over the local epidemic, thus they are more transmissible.”
The mutation to the spike protein has caused concern because this is one of the most effective parts of the virus, and the aspect which most treatments and vaccines are targeting.
For instance, the discovery of a “groundbreaking” antibody – that prevents the virus from infecting human cells – works by binding to this protein instead of allowing it to bind to cells and replicate.
The spike proteins are molecules on the outside of the virus which it uses to grab hold of and then penetrate the outer walls of human and animal cells.
There are two key features in the protein which have been attributed with its enormous infectious ability.
The first is called the receptor-binding domain (RBD), which they describe as “a kind of grappling hook that grips on to host cells”, while the second is known as the cleavage site, “a molecular can opener that allows the virus to crack open and enter host cells”.
The researchers acknowledge they do not know how the mutations have changed these key features.
However, the fact the team’s findings have not yet been peer-reviewed has concerned some observers, who fear the potentially alarming report should be rigorously analysed before being made public.
On the website hosting the study, one user suggested the “title of the manuscript seems a bit disingenuous” and warned that the prevalence of the mutated spike protein could be a matter of correlation rather then causation.
Although the mutated form of the virus is quickly out-competing the one initially detected in Wuhan, the researchers say they are not certain of their hypothesis that this is due to the spike protein mutation rather than another mutation.
Given the spike protein’s “vital importance both in terms of viral infectivity and as an antibody target, we felt an urgent need for an ‘early warning’ pipeline to evaluate spike pandemic evolution”, the study’s authors said.