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No evidence for increased transmissibility from recurrent mutations in SARS-CoV-2 – Nature

COVID-19 is caused by the coronavirus SARS-CoV-2, which jumped into the human population in late 2019 from a currently uncharacterised animal reservoir. Due to this recent association with humans, SARS-CoV-2 may not yet be fully adapted to its human host. This has led to speculations that SARS-CoV-2 may be evolving towards higher transmissibility. The most plausible mutations under putative natural selection are those which have emerged repeatedly and independently (homoplasies). Here, we formally test whether any homoplasies observed in SARS-CoV-2 to date are significantly associated with increased viral transmission. To do so, we develop a phylogenetic index to quantify the relative number of descendants in sister clades with and without a specific allele. We apply this index to a curated set of recurrent mutations identified within a dataset of 46,723 SARS-CoV-2 genomes isolated from patients worldwide. We do not identify a single recurrent mutation in this set convincingly associated with increased viral transmission. Instead, recurrent mutations currently in circulation appear to be evolutionary neutral and primarily induced by the human immune system via RNA editing, rather than being signatures of adaptation. At this stage we find no evidence for significantly more transmissible lineages of SARS-CoV-2 due to recurrent mutations.

https://web.archive.org/web/20201125121534/https://www.nature.com/articles/s41467-020-19818-2

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Opinion Videos

Prof Francois Balloux: the climate of fear on Covid is dangerous – UnHerd

Source: UnHerd, 8 Oct 2020
  • Scientists should not be involved in devising and implementing policies.
  • The window of opportunity to suppress the virus is gone.
  • The toll on public health caused by closed borders will be absolutely awful.
  • Indefinite suppression may not have ever been an option.
  • Vaccines may be helpful but won’t be a silver bullet.
  • The virus is here to stay.
  • Vaccines may be effective in reducing symptoms but we can’t gamble on an infection blocking vaccine.
  • Some vaccines aren’t always suitable for the entire population.
  • Banking everything on a vaccine is not a reasonable approach.
  • National level measures are not convincing; targeted measures have more potential.
  • Communication has been problematic so public trust has been lost.
  • Fear over a long period of time is physiologically unhealthy and doesn’t ever just evaporate.
  • The cost of allowing people to choose their own risk-level would be much lower than the current blanket proposals.
  • Well-targeted testing can be extremely effective but mass testing in schools is not a good use of tests.
  • The ‘medicalization’ of society is worrying.
  • Blanket testing of asymptomatic people is completely new and presents multiple ethical problems.
  • Proportion of asymptomatic cases for 2009 influenza pandemic was around 50%-75%; this is similar to what we’re finding COVID-19.
  • COVID-19 is not so different from other viruses but the global approach is completely different.
  • Normalising the mass testing of otherwise healthy testing is very dangerous.
  • There’s not much to be gained from comparing the measures and results between countries; the move to technocracy is dangerous.
  • Whole societies should not turn around public health.
  • A constant climate of fear is counter-productive.
  • There were other countries that took a similar approach to Sweden, such as Switzerland.
  • Past pandemics have been comparable to COVID-19 but did not have the same response.
  • Outbreaks in care homes is nothing new.
  • The pandemic phase of COVID-19 should eventually be over by mid to end of 2021 and in all likelihood become endemic.
  • The most important message: COVID-19 presents a severe health crisis but it is not a ‘new normal.’