More than 90% of Covid cases in the UK are now down to the coronavirus Delta variant first discovered in India, data has revealed, as the total number of confirmed cases passed 42,000.
Also known as B.1.617.2, the Delta variant has been linked to a rise in Covid cases in the UK in the past weeks. It is believed to spread more easily than the Alpha variant, B.1.1.7, that was first detected in Kent, and is somewhat more resistant to Covid vaccines, particularly after just one dose. It may be also associated with a greater risk of hospitalisation.
Now Public Health England (PHE) has revealed that up to 96% of new Covid cases in the UK involve the Delta variant, and that it has about a 60% increased risk of household transmission compared with the Alpha variant.
The report further revealed that cases of the virus are doubling between every 4.5 and 11.5 days, depending on the region, while confirmed cases to date have risen by 29,892 to 42,323.
The steep jump in cases is, in part, down to the use of a new technique to determine the variant present in a positive Covid sample. Previously, positive samples were sent to laboratories for whole-genome sequencing – a process that took five to 10 days to return results.
However, the new data includes results from a more rapid approach known as genotyping in which, rather than looking at the whole genome of the virus to work out which variant is involved, only key sections of the genome are examined. This gives results within 48 hours, with the report revealing it is highly accurate when it comes to picking up the Delta variant.
Using this approach, together with the more time-consuming genome-sequencing technique, the team says the most recent data shows 96% of Covid cases involve the Delta variant.
Dr Jenny Harries, the chief executive of the UK Health Security Agency, urged people eligible for vaccination to come forward to receive the jab.
“With numbers of Delta variant cases on the rise across the country, vaccination is our best defence,” she said, noting two doses provide significantly more protection than a single dose.
“However, while vaccination reduces the risk of severe disease, it does not eliminate it,” she added.
That is backed up by the data. According to the report, since the start of February to 7 June, there were 33,206 Delta cases: while 19,573 were in unvaccinated individuals, 1,785 were among fully vaccinated people and 7,559 were among those who had received one jab, with the vaccination status of the remainder unclear.
In total, 383 people were admitted to hospital with the Delta variant over that period – 223 of whom tested positive for Covid before turning up at A&E – with 42 having had two doses of the jab, 86 having one dose and 251 unvaccinated.
Of the 42 deaths recorded, 23 were in unvaccinated people, with 12 among those who were fully vaccinated and seven among people who had had one dose.
“With data showing that Delta is significantly more transmissible than Alpha, it is just as important as ever to follow public health advice, which has not changed,” said Harries.
“Get vaccinated, work from home where you can and remember ‘hands, face, space, fresh air’ at all times. These measures work, and they save lives.”