Has Covid-19 mutated into a more deadly strain? Busting the coronavirus myths
The truth about the
protective value of face masks and whether it’s easy to catch Covid-19
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Claim: it is mutating into a more deadly strain
All viruses accumulate mutations over time
and the virus that causes Covid-19 is no different. How widespread different
strains of a virus become depends on natural selection – the versions that can
propagate quickest and replicate effectively in the body will be the most
“successful”. This doesn’t necessarily mean most dangerous for people though, as
viruses that kill people rapidly or make them so sick that they are
incapacitated may be less likely to be transmitted.
Genetic analysis by Chinese scientists of
103 samples of the virus, taken from patients in Wuhan and other cities,
suggests that early on two main strains emerged, designated L and S. Although
the L strain appeared to be more prevalent than the S strain (about 70% of the
samples belonged to the former), the S branch of the virus was found to be the
ancestral version. The team behind this research suggested
that this may indicate the L strain is more “aggressive”, either transmitting
more easily or replicating faster inside the body. However, this theory is
speculative at this stage – there haven’t yet been direct comparisons to see
whether people who catch one version of the virus are more likely to pass it on
or suffer more severe symptoms.
Claim:
‘It is no more dangerous than winter flu’
Many individuals who get coronavirus will
experience nothing worse than seasonal flu symptoms, but the overall profile of
the disease, including its mortality rate, looks more serious. At the start of
an outbreak the apparent mortality rate can be an overestimate if a lot of mild
cases are being missed. But this week, a WHO expert suggested that this has not
been the case with Covid-19. Bruce Aylward, who led an international mission to
China to learn about the virus and the country’s response, said the evidence
did not suggest that we were only seeing the tip of the iceberg. If borne out
by further testing, this could mean that current estimates of a roughly 1%
fatality rate are accurate. This would make Covid-19 about 10 times more deadly
than seasonal flu, which is estimated to kill between 290,000 and 650,000
people a year globally.
Claim:
‘It only kills the elderly, so younger people can relax’
Most people who are not elderly and do not
have underlying health conditions will not become critically ill from Covid-19.
But the illness still has a higher chance of leading to serious respiratory
symptoms than seasonal flu and there are other at-risk groups – health workers,
for instance, are more vulnerable because they are likely to have higher
exposure to the virus. The actions that young, healthy people take, including
reporting symptoms and following quarantine instructions, will have an
important role in protecting the most vulnerable in society and in shaping the
overall trajectory of the outbreak.
Claim:
‘Face masks don’t work’
Wearing a face mask is certainly not an
iron-clad guarantee that you won’t get sick – viruses can also transmit through
the eyes and tiny viral particles, known as aerosols, can penetrate masks.
However, masks are effective at capturing droplets, which is a main
transmission route of coronavirus, and some studies have estimated a roughly
fivefold protection versus no barrier alone (although others have found lower
levels of effectiveness)..... read more:
https://www.theguardian.com/world/2020/mar/05/has-covid-19-mutated-into-a-more-deadly-strain-busting-the-coronavirus-myths