The Delta variant will inevitably dominate but what will its impact be?

Analysis: One dose of any vaccine reduces the chance of hospitalisation from the variant by 75%

The Covid-19 vaccine rollout is now hitting its peak, with 330,000 people due to be immunised this week.

The Covid-19 vaccine rollout is now hitting its peak, with 330,000 people due to be immunised this week.


You have to go back to summer 2020 for a time when public health officials were as optimistic about the progress of the Covid-19 pandemic as they are now.

With all indicators moving in the right direction and the dangerous Delta variant seemingly under control, their positivity is understandable.

It still begs a number of questions. What is different now from last year? Why are the trends different in Ireland from the UK? And just how much of a “black cloud” does the variant represent?

As of now, and despite widespread reopening of society since the start of May, the pandemic is shrinking at a rate of 3 per cent per day. The incidence of the disease is falling in all age groups aside from 19-24 year olds. Hospitalisations and ICU numbers are at their lowest in nine months. There were 24 deaths in May; just five reported so far this month.

The big difference from last year is vaccination, which is building a wall of protection around huge swathes of the population. Take-up is at least 90 per cent among those aged over 55. The rollout is now hitting its peak, with 330,000 people due to be immunised this week.

As Dr Tony Holohan pointed out, immunisation is resulting in the “near-elimination” of the virus in the vaccinated population. But this is having a wider and fortuitous knock-on impact for society. Cases among schoolchildren have fallen as their parents are vaccinated, for example. One or two patients or staff are picking up the disease in a hospital or other health setting, compared to 500 a week in January.

Cases rising in UK

The picture across the Irish Sea is very different. England has recorded 60,000 delta variant cases since February, with numbers almost doubling in the past week. Deaths linked to the variant, at 73, were also almost double the previous figure.

Across the UK, cases are doubling every 11 days, hospitalisations are increasing and deaths have stopped falling. Infections are spreading from younger people into older age groups and even a small proportion of vaccinated people are contracting the virus.

With the Delta variant now dominant, the UK government has been forced to postpone its last reopening by a month.

Both the UK and Ireland were slow to stop the importation of cases from India, where the variant was first identified, but the price each country paid for this delay is very different.

In Britain, prime minister Boris Johnson stands accused of not putting India on the “red list” for travel because he was planning to go there in April to sign a trade deal. The three-week delay saw an estimated 20,000 people come to the UK from India, thereby seeding hundreds of outbreaks.

Ireland, seemingly working off British data, waited even longer; it was early May before India was designated for mandatory hotel quarantine. Yet there has as yet been no surge in variant cases; in fact, the number of infections seems to be falling not rising. Of the 188 cases detected so far, 80 per cent are in and around Dublin.

I say “seems” because there is a two-week lag in reporting due to the time it takes to perform genetic sequencing. British scientists are using a new technique that gives results within days but this is still being validated for use here.

There is also uncertainty about the data since the cyberattack on the HSE’s IT systems over a month ago. Nonetheless, officials seem confident the variant is being kept in check thanks, they say, to an agile response from public health teams.

Quarantine and testing

But the Delta variant, which is 40-60 per cent more infectious than the currently dominant Alpha (UK) variant, will inevitably take over here; the only question is how long it will take.

Stiffer quarantine and testing arrangements have been imposed on travellers from Britain but not in respect of Northern Ireland, which is likely to be the main route of arrival of the variant into the Republic.

About one-quarter of all cases there are variants, five times the rate south of the Border, with Derry emerging as a hot-spot. The Northern authorities have already delayed the next phase of their reopening in light of the threat posed by the variant.

A recommendation against non-essential travel to the North could be on the cards, to judge by Dr Holohan’s comments at Thursday’s Nphet briefing. Whether politicians would be willing to run with that ball remains to be seen.

Whatever happens in the short term, even health officials are clear measures would only be needed for a few weeks. Covid-19 can still cause infection but its ability to induce serious illness is greatly lessened; even one dose of any vaccine reduces the chance of hospitalisation from the Delta variant by 75 per cent.

So while the pandemic has had many unforeseen twists, there is no reason at this stage to doubt that next month will see the lifting of further restrictions and the widespread resumption of air travel in Europe.