Maps show how BA.2 Omicron sub-variant has spread across UK in a week

MAPS show how fast the new Omicron sub-variant has spread in the UK in just one week.

The proportion of Covid cases caused by “BA.2”, or “Omicron’s sister”, have quadrupled in seven days, scientists say.

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The variant has spread to at least 40 countries since it popped up in November, mostly in Denmark, India and Sweden.

Some 426 cases of the new variant had been confirmed in the UK as of January 21.

However, data from the COVID-19 Genomics UK Consortium (COG-UK) says there have been 1,845 cases so far, mostly in England. 

The Wellcome Sanger Institute – which produces maps of variants spreading in the UK – reveals that BA.2 is now more common than Delta.

It accounted for an estimated 0.8 per cent of cases in the UK in the week to January 15 against Delta’s 0.5 per cent.

The figure has quadrupled in the space of one week, initially accounting for 0.2 per cent of cases in the week to January 8.

Omicron is still the dominating strain, accounting for more than 98 per cent of infections. 

Hotspots of BA.2 have now started to emerge, although cases are low.

Newham, in London, has the highest number of estimated cases (143), followed by Barnet (107) and Harrow (106).

Richmond upon Thames (104) and Brent (95) are other epicentres in the capital.

Outside of London, Northampton has a predicted 109 cases of the BA.2 strain, while Liecester has 92 and Wiltshire has 85.

Not to worry yet…

BA.2 is very genetically similar to the original Omicron.

Prof Francois Balloux, Professor of Computational Systems Biology and Director, UCL Genetics Institute, UCL, said the two strains are “about 20 mutations apart”. 

It means anyone who has already had the fierce Omicron variant is likely to have “robust immunity” against the new one.

BA.2 appears to be able to spread faster, however, according to data from the UK Health and Security Agency (UKHSA).

But it isn’t thought to be any more severe.

A string of positive studies show Omicron is milder than other strains in the vaccinated – with vaccines thought to still be effective against this new variant, BA.2.

Health officials in Denmark, who have seen the most cases of BA.2 so far, say Covid vaccines are thought to still be as effective.

BA.2 is missing a key mutation that allows labs to discover and then flag up cases, which makes it harder to track.

To detect if a person is infected with this variant, their swab would need to be sent to a laboratory for genetic sequencing.

However the general scientific opinion is that BA.2 is nothing to worry about currently. 

Dr Meera Chand, COVID-19 Incident Director at UKHSA, said on Friday: “It is the nature of viruses to evolve and mutate, so it’s to be expected that we will continue to see new variants emerge as the pandemic goes on.”

Health and Social Care Secretary, Sajid Javid, said: “We are learning to live with this virus – and thanks to our world-leading surveillance system we can rapidly detect and carefully monitor any genetic changes to Covid-19.”

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