Q&A: Why do we have so many coronavirus infections?

Expert virologist casts a cold eye on cause and effect – plus ‘fighting on all fronts’

Why does Ireland have so many Covid-19 cases when so many people are vaccinated and have had booster doses?

That's a good question, which attempts were made to answer earlier in the pandemic. But with Omicron variant now dominant and case numbers hitting stratospheric levels, it's time to try again – this time with the help of University College Dublin virologist Dr Gerald Barry.

Is Ireland no worse than any other country?

Hospital Report

No, the only countries with higher incidences of Covid-19 at the end of December were Cyprus and two micro-states, Andorra and Aruba, according to Our World in Data.

With 77 per cent of the total population having received their shots, Ireland is in the top handful of European states for vaccination. And, as Taoiseach Micheál Martin noted on Wednesday, Ireland now leads the EU in terms of booster uptake among adults, at 57 per cent.

Things can change very fast in Covid-land, but for now the graph of infections in Ireland is still going upwards.


Okay. Then why are things so bad at the moment?

As Dr Barry notes, the answer is influenced by multiple factors that we know about and some that are less apparent. In the autumn there were factors specific to Ireland: our location close to England and to Northern Ireland; the relative importance of international travel; our relatively young population, who are therefore more likely to socialise; the relative dearth of single-occupier accommodation here, and so on.

There is clearly a seasonal element to these waves of infection. And it is remarkable that Europe, the most heavily vaccinated region in the world, has been at the epicentre of so many of them.

There were factors that should have worked against the spread of infection, such as our relatively remote island location, the high adherence to public health measures and our relatively long and strict lockdown. All of these factors are still relevant when searching for an answer to the question.

So are there new factors that might explain what is going on?

Just as in the autumn, the latest Omicron wave started from a higher base than in other countries because Ireland never managed to get case numbers down to low levels.

Socialisation over Christmas was a key factor, Dr Barry believes, with many infections in workplaces, schools and universities remaining undetected and then being brought into homes and across communities over Christmas.

Did Omicron play a role?

With the more transmissible variant now dominant, the impact of this socialisation, in terms of the spread of infection, is greatly multiplied.

The other feature of the variant is its greater immune escape. As a result, the wall of protection Ireland had constructed through high vaccination rates became less sturdy. It also became apparent that the protection provided by vaccines against infection wanes quickly (So, it seems, does booster protection).

“If a person has a booster then there is about 75 per cent protection against symptomatic infection but without a booster that protection is reduced to less than 30 per cent,” Dr Barry says. “Also booster protection takes about 10 days to two weeks to kick in fully.”

So, because many people got their booster just before Christmas, they had “limited protection” against infection.

Oh dear, that sounds ominous, right?

Remember, though, that vaccines and boosters are not there to stop infection; they were invented to keep people from becoming seriously ill.

So while Ireland is suffering a lot of cases, fewer and fewer of these are converting into hospitalisations and, especially, intensive care (ICU) admissions. According to the Taoiseach, many of those in ICU actually have the previously dominant Delta variant.

“Vaccines are doing their job to a great extent, but because they aren’t perfect some leakage into hospitals will occur,” says Dr Barry.

Why have we so many cases when we’re so highly boosted?

“Even asking the question points to the root of our problem in Ireland and in many parts of the world,” suggests Dr Barry. “We are using a tool that isn’t designed to stop infections and then wondering why it didn’t stop infections.

"It's like putting Ronaldo at centre back and then asking why his team concedes so many goals. The vaccine is amazing and will do a job in defence but it isn't the perfect tool, it isn't Paul McGrath or Virgil Van Dijk. "

He suggests the State’s massive reliance on vaccines, and failure to bolster defences with other tools, means “we aren’t really fighting on all fronts”.

“I would strongly advocate for a complete reassessment of everything we have done to this point, identify everything else that could be done that would help, knock off everything that isn’t feasible or is unaffordable and do everything else.”

So have we failed?

The problem with a “do more” strategy is that some countries that have demonstrably done less to curb the spread of infection, such as England, seem to be doing better overall.

Mind you, an obsession with case numbers is misplaced. What matters is serious infection. Ireland is well below average in terms of Covid-19 deaths. Before Christmas, we also had relatively low level of hospitalisation; our problem is a shortage of hospital and ICU beds.

Overall, therefore, we’re a mixed bag; some high points, some failures and so many unknowns.