Just five per cent of Indian variant infections are in people who have been fully vaccinated, latest figures show.
A Public Health England (PHE) briefing on the new variant that has been sweeping Britain, also known as the Delta variant, shows that the disease is predominantly affecting people who have yet to receive the jab.
Out of 33,206 cases sequenced since February 1, just 1,785 were in people who had been fully vaccinated and only 62 ended up being admitted to hospital compared with 397 of unvaccinated individuals.
The new data also show that the death rate is still very low with just 0.1 per cent of people catching the variant going on to die – 1 in 1,000 – although this may increase in the coming weeks because of the lag between cases, admissions and deaths.
In comparison, the death rate for people catching the Kent (or Alpha) variant is 1.7 per cent – 17 in 1,000.
So far there have been just 42 deaths from the Delta variant, and only 12 in fully vaccinated people. NHS leaders have previously said that those dying after being fully vaccinated are also suffering from "profound co-morbidities".
Commenting on the report, Meaghan Kall, an epidemiologist from PHE said: “Hospitalisation and deaths remain low considering case numbers
“The great news is that vaccines are still working against infection and severe disease. Given Delta is dominant in all England regions, what I find interesting is that we aren’t seeing huge increases in case rates in all areas.
“Delta cases are still concentrated in a dozen or so areas. It spreads rapidly there in unvaccinated populations, driving up R nationally.”
Cases of the Delta variant have jumped from 9,426 last week to 33,206, and now make up 96 per cent of all genotyped infections, but experts cautioned the large increase was due to cases being detected using a new form of test which has cut the time to get results from 7-21 days to just 36 hours.
It is estimated that the current doubling time is between 4.5 days and 11.5 days.
There are still concerns that the Delta variant increases the risk of hospitalisation 2.6 fold and A&E admission by 50 per cent in comparison with the Alpha variant, although this appears to be mitigated by vaccination.
However, the latest data also show that the number of people being infected by a carrier has also dropped, from 13.5 per cent to 11.3 per cent in the last two weeks.
Layla Moran, the Lib Dem MP and chairwoman of the All-Party Parliamentary Group on Coronavirus, said the figures should "set alarm bells ringing" in Government ahead of Freedom Day on June 21.
“Simply letting this highly contagious strain of the virus rip through unvaccinated younger people risks leaving more with long Covid and creating a ticking time bomb for our NHS,” she said.
The PHE figures also showed that two thirds of the 1,234 people with the Delta variant who attended A&E in England between February 1 and June 7 were unvaccinated.
Of the 383 cases where attendance at A&E resulted in an overnight admission, 251 (66 per cent) were unvaccinated, and just 42 (11 per cent) were more than 14 days after someone had had a second jab.
Dr Jenny Harries, chief executive of the UK Health Security Agency, said: “With numbers of Delta variant cases on the rise across the country, vaccination is our best defence.
“Remember that two doses provide significantly more protection than a single dose. However, while vaccination reduces the risk of severe disease, it does not eliminate it.
"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.”