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By James Gallagher
Health and science correspondent
Published 1 day ago
It is clear we are now dealing with a virus that spreads far more easily - probably more than twice as easily - as the version that emerged in Wuhan at the end of 2019.
The Alpha variant, first identified in Kent, UK, performed a large jump in its ability to transmit. Now Delta, seen first in India, leapt further still.
This is evolution in action.
... There are examples of viruses, she said, from flu pandemics to Ebola outbreaks, making the jump and then accelerating.
So how far could it go?
The cleanest way of comparing the pure biological spreading power of viruses is to look at their R0 (pronounced R-naught). It's the average number of people each infected person passes a virus on to if nobody were immune and nobody took extra precautions to avoid getting infected.
That number was around 2.5 when the pandemic started in Wuhan and could be as high as 8.0 for the Delta variant, according to disease modellers at Imperial.
Chart: How the R0 numbers of Covid-19 variants and other diseases compare
Health and science correspondent
Published 1 day ago
It is clear we are now dealing with a virus that spreads far more easily - probably more than twice as easily - as the version that emerged in Wuhan at the end of 2019.
The Alpha variant, first identified in Kent, UK, performed a large jump in its ability to transmit. Now Delta, seen first in India, leapt further still.
This is evolution in action.
... There are examples of viruses, she said, from flu pandemics to Ebola outbreaks, making the jump and then accelerating.
So how far could it go?
The cleanest way of comparing the pure biological spreading power of viruses is to look at their R0 (pronounced R-naught). It's the average number of people each infected person passes a virus on to if nobody were immune and nobody took extra precautions to avoid getting infected.
That number was around 2.5 when the pandemic started in Wuhan and could be as high as 8.0 for the Delta variant, according to disease modellers at Imperial.
Chart: How the R0 numbers of Covid-19 variants and other diseases compare