Covid Delta variant 40% more transmissible, Matt Hancock says

Sage scientists warned last month the mutation could lead to a ‘much larger peakl’ if it was 40% more infectious

The Delta variant of Covid-19 first detected in India which is spreading widely in the UK is believed to be 40 per cent more transmissible than previous mutations of the virus, the health secretary has said.

During an interview with the BBC’s Andrew Marr on Sunday morning, Matt Hancock said the heightened infectiousness of the variant – which is now believed to be the dominant mutation in the UK – made “life more challenging for everybody”.

The Sage scientific advisory committee warned last month that if the Delta variant were to be 40 to 50 per cent more transmissible it could lead to a “much larger peak” than previous waves of the virus seen at the start of this year and last spring, when tens of thousands of people were hospitalised and died.

In a report from a Sage video meeting held on 13 May, the panel concluded that if the Delta variant were to have a 40 to 50 per cent “transmission advantage nationally compared to B.1.1.7 [otherwise known as the Alpha, Kent or UK variant]”, then progressing with step 3 of the unlocking on 17 May “would lead to a substantial resurgence of hospitalisations (similar to, or larger than, previous peaks)”.

The report added that further easing of restrictions under step 4 of the government’s Covid roadmap on 21 June “could lead to a much larger peak”.

Mr Hancock said on Sunday: “The best estimate of the growth advantage, as we call it, of the Delta variant, from Sage is around 40 per cent.

“So that does make life more challenging for everybody and you’ve seen that the case rates have risen a little.”

Asked about the Sage prediction, Mr Hancock said: “That was a few weeks ago and we have got more data since then. The thing that we are watching incredibly carefully is of course the case rate, but also the rate in which that translates into hospitalisations, and thankfully that link which was absolutely rock solid, sadly, over the autumn, that link now is severed but not broken.

“There are some people in hospital who have been double vaccinated, but very few. The majority of people in hospital haven't [had the vaccine], and critically those who are double vaccinated also appear to be, even if they are in hospital, less seriously ill.

“So the vaccine is working and it is our way through it, but the new variant, because it is more transmissible, is obviously making that calculation harder, and we’ll look at the data for another week and then make a judgment [on whether to proceed with unlocking on 21 June].”

Mr Hancock added: “The good news is that the hospitalisations, the number of people arriving at hospital is broadly flat, and the majority appear to be those who have not had a vaccine at all. And only a very small minority of people who have had both jabs.

“So the best scientific advice I have is that after one jab, it is not quite as effective against the new Delta variant but after both jabs, it is. Which is why it is so important that we drive through these vaccinations and that people come forward for their second jabs.”