The truth about the protective value of face masks and how easy it is to catch Covid-19
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 doesnt 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 havent 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 countrys 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.
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