Imperial’s Professor Neil Ferguson says the next stage of the UK’s roadmap out of lockdown is ‘in the balance’ as variant B1.617.2 becomes dominant.

The variant B1.617.2, which was first detected in India, is currently driving an increase in cases in the UK.

Professor Ferguson said: " The variant is now in well over the majority of Local Authority areas in the country and is now the dominant strain. This means the majority of new cases are of the Indian variant and that’s concerning.

We also know it also partially evades immunity generated by vaccines. The data collected in the next two to three weeks will be critical for determining whether step 4 can go ahead safely. It is very much in the balance right now."

Next stage of roadmap

Step Four of the UK government's roadmap out of lockdown for England would see all restrictions lifted from June 21st.

The latest ONS infection survey suggests less than 1 in 1,000 are infected in England.

Professor Ferguson added: "It was always expected that relaxation would lead to a surge in infections and a small third wave of transmission, that’s inevitable if you allow contact rates of the population to go up, but we can’t cope with that being too large."

Determining how transmissible the new variant is will be vital in the government's decision to continue with the roadmap as planned.

Professor Ferguson said: "The roadmap is robust to a certain level of increase in transmissibility of the virus and a certain level of immune escape.

"If it goes beyond those levels we may need to reconsider rate of reopening and maybe slow the next step.

" A scenario where a variant is 60% more transmissible and has a significant degree of immune escape could lead to another third wave the size the UK has just come out of. But if the level of transmissibility increase is only 20% or 30% and has only marginal evasion of immunity, then the third wave is predicted to be much smaller and therefore manageable. "

Variant first detected in India

Professor Ferguson believes that the B.1.617.2 variant is definitely more transmissible than B.1.1.7, known as the Kent variant, but it will take another two to three weeks for more data to confirm the extent of this.

The B.1.1.7 variant is thought to be around 60% to 70% more transmissible than variants of coronavirus that came before it.

Professor Ferguson says that the UK has been much more heavily seeded with the variant first detected in India than other countries in Europe because of its historically higher levels of travel to and from India.

Higher case rates in under 21s

Professor Ferguson says that there is a 'signal' in the data that under 21s are slightly more likely to be infected with this variant than other variants.

However, this may have nothing to do with the biological properties of the virus and may be a factor of the communities, schools and colleges in which it’s been seeded.

Professor Ferguson said: "There's no indication at the moment that this is more severe in children than other variants."

Professor Ferguson was speaking at a Science Media Centre Germany briefing alongside Professor Ravindra Gupta from the University of Cambridge.