I
can scarcely overemphasise the importance of this. It puts doubt on
everything from developing ‘herd immunity’ to a vaccine.
I
am somewhat surprised that the NZ Herald published this.
Covid
19 coronavirus: Mutation threatens race to develop vaccine
14
April, 2020
A
coronavirus strain isolated in India carried a mutation that could
upend vaccine development around the globe, according to researchers
from Australia and Taiwan.
The
non-peer reviewed study said the change had occurred in part of the
spike protein that allows the virus to bind with certain human cells.
This
structure targets cells containing ACE2, an enzyme found in the lungs
which also allowed the severe acute respiratory syndrome (Sars) virus
to infect people.
Scientists
know more about this receptor than any other so had been working on
antibodies that target it, but an unexpected structural change could
render them useless.
The
researchers – led by Wei-Lung Wang, from the National Changhua
University of Education in Taiwan, and collaborators from Murdoch
University in Australia – said this was the first report of a
significant mutation that could threaten development of a vaccine for
the virus that causes Covid-19.
"The
observation of this study raised the alarm that Sars-CoV-2 mutation
with varied epitope [something an antibody attaches itself to]
profile could arise at any time," they wrote in a paper released
on preprint review site biorxiv.org on Saturday.
"[This]
means current vaccine development against Sars-CoV-2 is at great risk
of becoming futile."
Although
the strain in question was first sampled by the National Institute of
Virology from a patient in Kerala as early as January, the full
genome sequence was only released to the international community last
month – a delay that raised eyebrows among some researchers.
The
patient was said to be a medical student returning from Wuhan, but
the strain does not appear to be closely related to any of those
identified in the Chinese city and appears to be an outlier compared
with variants recorded in other countries.
The
researchers found that the mutation occurred in the spike protein's
receptor-binding domain (RBD).
A
computer simulation shows that the RBD mutation, which was not found
in other variants across the globe, could remove a hydrogen bond from
the spike protein
Without
this bond, the virus may be less likely to bind with ACE2, or
angiotensin converting enzyme-2, which is found in the lungs and
other organs.
The viral strain identified in India contains a mutation that could undermine current efforts to develop a vaccine.
The viral strain identified in India contains a mutation that could undermine current efforts to develop a vaccine. Photo / AP
Since
its first confirmed identification in early January, the virus has
reached every continent except for Antarctica with more than 3500
mutations detected, according to the China National Centre for
Bioinformation.
For
a long time India appeared to have been spared by the Covid-19
pandemic, but it has now recorded around 9000 confirmed cases.
The
virus' presence in the country has grown rapidly in recent weeks,
with cases being identified in crowded slum areas, and scientists
fear the world's second biggest country could see the next major
outbreak – something that threatens a humanitarian disaster.
The
international community still knows relatively little about the
evolution and spread of the virus due to limited testing and
information from the subcontinent.
A
researcher with the Chinese Academy of Sciences in Beijing who is
tracking the mutation of the coronavirus said he was closely
monitoring the emerging strains from India.
Some
vaccines have already started clinical trials in China and the US,
but the RDB mutation could create more uncertainty about the eventual
outcome.
The
findings of the new study, which was not peer-reviewed, will need
further verification. For instance, there was a possibility that the
mutation was caused by a technical error during the sequencing
process, according to the researcher, who requested not to be named
due to the sensitivity of the issue.
He
also said the results produced by the computer simulation may be
misleading.
"Laboratory
experiments will be needed to verify whether the protein changes in
real life," said the researcher.
The
unusual behaviour of the coronavirus has kept scientists around the
world scratching their heads. For instance, it has infected a large
number of patients around the world but the genetic structure of the
strain has remained relatively stable.
Some
researchers have speculated that it might have been spreading quietly
in humans for a long time and evolved to a form that did not require
too many changes to adapt to different environments and populations.
But
others worry the thousands of strains sampled and sequenced are just
the tip of the iceberg – and greater variety increases the risk
that new strains will require new vaccines in the same way the flu
virus does.
Although
China has five different vaccines under development "it is
impossible to predict which one is more likely to succeed", said
the researcher. "They could all end in failure."
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