THE DELTA VARIANT of the coronavirus now accounts for 99% of confirmed and probable cases across the UK.

In just one week there has been a 79% rise in cases of this variant, with the British government forced to implement a four-week pause on the full lifting of restrictions in England as they race to vaccinate the population and control this more transmissible strain.

The data shows that 75,953 confirmed and probable cases of the Covid-19 Delta variant have now been found in the UK – up by 33,630 on the previous week. Of the 75,953, some 70,856 have been in England, 4,659 in Scotland, 254 in Northern Ireland and 184 in Wales.

The increase in Covid-19 cases all across the UK is being driven by younger, unvaccinated age groups, public health officials have said. These younger age groups have now been invited for a vaccination as the jab rollout extends to anyone aged 18 and over.

While the Delta variant is now the most dominant in Britain – and is likely to soon become the most dominant in Northern Ireland – Delta case numbers in the Republic of Ireland have remained at a stable level, with no signs, for now, of sudden surges that have been seen in England in particular.

Speaking to The Journal, Dr Fidelma Fitzpatrick consultant and senior lecturer in microbiology at the Royal College of Surgeons (RCSI) explained that the Alpha variant, formerly known as B117, which arrived in Ireland just before Christmas, is still the dominant strain here.

To date there have been 180 cases of the Delta variant identified in Ireland, which accounts for just 5% of sequenced cases.

“We’re still not seeing that explosion that they’ve seen in Britain,” Dr Fitzpatrick said.

HSE HSE

She said she believes the vaccination has been key to keeping levels of this variant low.

Data from Public Health England shows both the Pfizer and AstraZeneca vaccines are effective against this variant – if a person has had their full two-dose schedule.

Both vaccines offer almost 50% protection against the Alpha variant after one dose but this drops to about 36% for the Pfizer vaccine and 30% for the AstraZeneca jab when they come up against the Delta variant. 

Two weeks after the second dose of the Pfizer vaccine it offers 88% protection against symptomatic disease with the Delta variant and 96% protection against hospitalisation, while the AstraZeneca jab offers 67% protection against symptomatic disease and 92% protection against hospitalisation.

Data shows the increase in cases in England have been primarily in younger age groups who are not yet vaccinated.

While cases of the #Delta #COVID19 variant are rising rapidly across the country, the increase is primarily in younger age groups who are now being invited to receive the #vaccine. pic.twitter.com/8d0weaCvrq

— Public Health England (@PHE_uk) June 18, 2021

As of 14 June, 806 people in England have been admitted to hospital with the Delta variant of Covid-19, a rise of 423 on the previous week, according to Public Health England data.

Of the 806 admitted, 527 (65%) were unvaccinated, 135 (17%) were more than 21 days after their first dose of vaccine, and 84 (10%) were more than 14 days after their second dose.

As of June 14, there have been 73 deaths in England of people who were confirmed as having the Delta variant and who died within 28 days of a positive test. Of this number, 34 (47%) were unvaccinated, 10 (14%) were more than 21 days after their first dose of vaccine and 26 (36%) were more than 14 days after their second dose.

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Data from Ireland’s Health Protection Surveillance Centre (HPSC) indicate a similar age-related trend in Ireland, with 57.9% of reported Delta cases among those aged 19-34 and a further 11.9% in those under the age of 18. 

Almost 20% of cases with the Delta variant are among those aged 35-44, dropping to 9.5% in the 45-64 age group. Less than 1% of cases of this strain are among those aged over 65, the majority of whom have now received at least one dose of vaccine, while a significant proportion are fully vaccinated.

“To me, that tells me that’s vaccination making that impact,” Dr Fitzpatrick said. “The vaccination programme has been a game-changer here, we’ve seen that in hospitals in particular where in December and January we had lots of positive cases and suddenly those numbers just fell off a cliff.”

The fact that Ireland has had tighter restrictions in place nationally, as well as travel measures such as mandatory hotel quarantine and PCR testing, has also likely helped keep a Delta surge at bay.

“England has a bigger population and also historic links with countries where Delta originated, moreso than we have,” she said.

The Delta variant was first identified in India and spread rapidly throughout the country, causing hospitals to become overwhelmed. 

“If you look at the data here, travel history is a factor in a significant proportion of cases, followed by close contacts. So you have people travelling in who have it and then surprise, surprise, their close contacts become positive as well, which is what you’d expect,” Dr Fitzpatrick said.

So in terms of mandatory hotel quarantine and at home quarantine, everything that contains it helps. The idea behind the quarantine period is that you’re staying in one place for that period of time, so you could be negative at the start of the week but then positive later on and this limits the spread. 

While restrictions both nationally and in terms of travel clearly help keep control of transmission levels, it is not a longterm solution.

“Definitely restrictions limit the spread. Now there are obviously consequences for other sectors of society, but our restrictions have been more more stringent than in the UK,” she said.

“The lesson we’ve learned about Covid is that the virus is very transmissible and some variants are even more transmissible, once it gets in it can spread and you need a mixture of infection control and public health measures and then also a strong vaccination programme.

“Of course if everyone stays home it won’t transmit but we can’t keep everyone locked up forever, that’s no way to live, so that’s why vaccination is going to be so important going forward.”

- With reporting from PA.