By Rachel SchraerHealth reporter
image copyrightGetty Images
A variant of the Covid-19 virus first discovered in India is responsible for the majority of new cases in pockets of England.
One of three subtypes of the virus identified on the subcontinent, variant B.1.617.2 is thought to spread more easily – but what does that mean for you?
At least five cases of the variant have been identified in 86 local authorities, according to Health Secretary Matt Hancock. That doesn’t mean it’s not circulating elsewhere – but it also doesn’t mean all 86 are being overwhelmed by the variant.
There are particular clusters in north-west England and in London.
In some areas – including in Bolton, Blackburn, Sefton in the North-West and Bedford, Chelmsford and Canterbury in the South-East – this version of the virus is causing the majority of infections. In London it makes up the lion’s share of cases in Croydon, Hounslow and Hillingdon.
There is evidence a surge in Glasgow, leading the city to remain under restrictions as lockdown lifts, is being driven by the variant.
As of 12 May, 1,255 cases had been identified in England, 35 in Scotland, 12 in Northern Ireland and 11 in Wales. Numbers will have risen since then.
Just because it’s the most common strain doesn’t mean there’s lots of it about.
In Bolton, the most concerning area, 289 cases have been analysed in the past week according to the Wellcome Sanger Institute, which is carrying out genetic surveillance of the virus. There were 110 cases identified in the past week in Blackburn, 99 in Sefton and 69 in Bedford (this is almost certainly an underestimate of how many are actually circulating).
But in Croydon, for example, roughly three-quarters of cases amounts to only 14 individual infections that could be attributed to the B.1.617.2 variant.
This strain of the virus seemed to behave quite differently in different parts of the country – cases shooting up in Bolton and Bedford but growing much more slowly in London.
This suggests people’s movement and contact patterns are at least partly driving the rise.
In parts of the country with very few cases, such as Yorkshire and south-west England, the majority of infections have been confined to people returning from India.
But in the North West, which is most affected, only 7.5% of cases were in people who had travelled, showing the virus had spread further into the community.
It’s been pointed out some of the worst-affected areas have very low proportions of residents who are able to work from home.
The government says it does appear to spread more easily than the Kent variant (B.1.1.7), which was behind the UK’s huge winter spike in infections.
Its scientific advisers, who try to predict the course of the pandemic using mathematical models, say they are “confident that B.1.617.2 is more transmissible than B.1.1.7, and it is a realistic possibility that this new variant of concern could be 50% more transmissible”.
There is still plenty of uncertainty around this, though – they define a “realistic possibility” as meaning the odds are about 50-50.
And untangling the behaviour of the virus from the behaviour of humans is always a big challenge.
The government’s scientific advisers point to the way the variant identified in India has outstripped the Kent variant in affected areas, suggesting it is better at spreading.
But it’s still plausible this could be the result of human behaviour – if lots of people returned from India to an area where many live in overcrowded housing or have to work outside the home, at a time when there wasn’t much of the Kent variant around, it could take off without being innately any better at spreading.
Figures from NHS Test and Trace, which can track who’s actually catching the virus, point towards a lower “attack rate” than you’d expect if it was in fact 50% more infectious.
It’s too early to really know this.
There is currently little evidence in people that the variant is overcoming the vaccine.
In the case of other variants, such as that first identified in South Africa, the vaccine appears to have fought them off better than initially feared.
But the Scientific Pandemic Influenza Group on Modelling (SPI-M) says: “At this point in the vaccine rollout, there are still too few adults vaccinated to prevent a significant resurgence that ultimately could put unsustainable pressure on the NHS.”
Despite fears over the new variant, most of the UK went ahead with easing restrictions on 17 May.
A close watch will be kept on the data before any decision is made about what happens on 21 June, when the next stage of easing is scheduled.
Many countries already have bans on people from the UK and elsewhere entering.
But we don’t yet know whether others will follow suit specifically in response to the variant from India.