Delta Variant ‘60% More Transmissible’ than Kent Strain, Warns Scientist


  • The Delta variant of coronavirus, first discovered in India, is anywhere between 30% to 100% more transmissible than the previously dominant Alpha (or Kent) variant.
  • Prof Neil Ferguson sounds warning as remaining lockdown restrictions are due to be lifted 21 June.

The COVID-19 variant first identified in India is thought to be around 60% more transmissible than the Kent variant, reports the Guardian quoting one of Britain’s leading scientists.

Rapid spreading variant

Professor Neil Ferguson, an Imperial College London epidemiologist, added that the B1.617.2 variant, also now known as Delta, could spread between 30 and 100 per cent more easily, but a central estimate was around 60 per cent.

He stressed that the data this week was in a more “negative direction” than earlier, casting growing doubts on whether the Government will be able to go ahead with the final easing of lockdown on June 21.

Sixty per cent higher transmissibility would be at the higher end of what was feared by many scientists.

It will also spark fresh questions over why the Government did not act more quickly to put India on the “red” list of countries to limit arrivals into the UK.

60% more transmission! 

Prof Ferguson, whose work was key to the Government ordering the first lockdown in March 2020, told: “We are certainly getting more data and unfortunately the news is not as positive as I would like on any respect about the Delta variant.”

The best estimate at the moment is this variant may be 60 per cent more transmissible than the Alpha (Kent) variant,” he said.

He added, “There is some uncertainty around that – depending on assumptions and how you analyse the data – between about 30 and maybe even up to 100 per cent more transmissible.”

Sixty per cent is a good central estimate at the moment.”

A difficult judgement call 

He also explained: “It partially escapes vaccine immunity although there is still a good deal of protection and may well cause more severe disease from new hospitalisation data.”

Most people, though, being hospitalised at the moment with COVID-19 are unvaccinated, he added.

So it’s clear that the vaccines are still having a substantial effect but it may be slightly compromised,” he stressed.

On whether the June 21 ending of lockdown restrictions should happen, he explained: “The data is pointing this week in a more negative direction than it was last week. So, it points towards the direction of being cautious.”

I think balancing people’s desire, and there clearly is a built-up desire to get back to normal, against the potential risks is a very difficult judgement call.”

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Source: The Guardian


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