Cumulative case rates for Ireland were in line with the EU27 average until the end of November 2020, but subsequently grew at a slower rate until the end of October 2021, with COVID-19 case numbers increasing more rapidly thereafter.
By the end of November 2021, a total of 570,115 cases of COVID-19 had been confirmed in Ireland.
HIQA examined trends in five epidemiological indicators including:
- Confirmed cases of COVID-19,
- Hospitalisations (new admissions and total patients) with COVID-19,
- Intensive care unit (ICU) admissions and total patients in ICU with COVID-19,
- Reported COVID-19 deaths,
- Excess mortality (that is, above what would normally be expected).
The analysis was carried out at the request of the Department of Health, and reviewed data for the 27 EU member states (EU-27) and Norway, Switzerland, Ukraine, and the UK.
Two peaks in hospital and ICU admissions in Ireland occurred in April 2020, and January 2021. Other European countries also experienced significant increases in hospitalisations around these times.
However, the surges in hospitalisations experienced in Ireland were lower and of a shorter duration than those experienced by many European countries.
Notably, the data does not distinguish between people admitted to hospital due to COVID-19 from those who were admitted to hospital for other reasons, but who tested positive for SARS-CoV-2.
In Ireland, there were two peaks in reported COVID-19 deaths in April 2020, and February 2021.
However, these peaks in mortality were typically shorter in duration than those that occurred in other European countries.
There were 5,514 COVID-19 deaths reported in Ireland up to 30 November 2021. The cumulative rate of recorded COVID-19 deaths per million population in Ireland remained consistently below the EU27 average throughout.
The criteria for recording deaths as COVID-19 deaths differed across European countries and, in some countries, changed over time – thus limiting direct comparisons, HIQA has pointed out.
Overall, 91% of recorded COVID-19 deaths in Ireland occurred among those aged 65 or older, with 22% occurring in those aged 85 and older.
In 2020, the cumulative rate of reported COVID-19 deaths in Ireland of those over 65 exceeded that of the EU27 average but, in 2021, this death rate slowed to lower than the EU27 average.
Excess deaths are calculated by estimating the expected number of ‘all-cause’ deaths for a particular time period, based on historical trends, and then subtracting these from the actual number of all-cause deaths observed during that time.
There were an estimated 2,019 excess deaths in Ireland between 2 March 2020 and 28 November 2021.
The excess deaths occurred during a seven-week period from late March to mid- May 2020; and an eight-week period from early January to late February 2021.
No consecutive weeks of excess deaths occurred outside of these periods.
There was substantial variability in the magnitude and duration of peaks in excess mortality across European countries throughout the study period.
Between mid- and late-2021, the excess mortality in Ireland was observed to be among the lowest in Europe.
The majority (82%) of excess deaths in Ireland occurred among those aged 65 or older. Excess deaths in this age cohort occurred during two distinct peaks, with similar excess mortality across the two waves.
Across all countries, large variation was observed in the timing, magnitude and duration of COVID-19 peaks in terms of cases, hospital admissions and mortality, particularly between October 2020 and June 2021.
Ireland has a smaller proportion of older adults relative to most countries within Europe, with 13.9% of the population aged 65 or older (EU27 average: 18.7%) and 8.7% of the population aged 70 or older (EU27 average: 12.4%), based on data collected in 2015.
Other European countries also experienced significant increases in hospitalisations around these times, with several experiencing peaks that were higher, and of a longer duration, than in Ireland.
Chief scientist Dr Conor Teljeur said: “The purpose of this report was to provide a high-level summary of key epidemiological indicators relating to the burden of COVID-19 across European countries, over the course of the pandemic, and prior to the emergence of the Omicron variant in Ireland.”
Several factors influenced the course of the COVID-19 pandemic here, he said.
“Ireland has a relatively young population and a lower population density compared to most other European countries, but a much higher proportion of people living in households of three or more persons,” he said.
Lower population densities may lead to reduced SARS-CoV-2 transmission as it may be less challenging to follow advice regarding social distancing.
A full 44.8% of Irish households consist of more than three people, with just 25.7% living in one-person households.
Hospital capacity may influence admission and discharge policies, the report says.
And vaccine rollout, which began in early 2021, prioritised the most vulnerable with most over-70s inoculated by June of that year.
However, variable approaches to COVID-19 testing, public-health restrictions, and vaccine rollouts limit the conclusions that can be drawn from comparing the burden of the pandemic across countries, he concluded.