"A Profile of COVID-19 in Ireland – Using Census 2016 Household Data to Analyse COVID-19 Cases from March 2020 to May 2021" is an update to the CSO Frontier Series publication A Profile of COVID-19 in Ireland - Using Census 2016 Household Data to Analyse COVID-19 Cases from March to November 2020. It is based on confirmed COVID-19 cases from the Computerised Infectious Disease Reporting (CIDR) data set provided to the CSO by the Health Protection Surveillance Centre (HPSC) which was matched to people enumerated on Census Night 2016. 

This publication is categorised as a CSO Frontier Series Output. Particular care must be taken when interpreting the statistics in this release. CSO Frontier Series may use new methods which are under development and/or data sources which may be incomplete, for example new administrative data sources. Publishing outputs under the Frontier Series allows the CSO to provide useful new information to users and get informed feedback on these new methods and outputs whilst at the same time making sure that that the limitations are well explained and understood. In using the increasingly varied sources of data available, the CSO must ensure that we continue to protect and secure data. Our aim is to ensure that citizens can live in an informed society while at the same time ensuring adherence to all relevant data protection legislation. In this report, of the 254,013 confirmed cases of COVID-19 in the CIDR dataset up to and including 12 May 2021, 70% (178,620 cases) were successfully linked to the CSO’s pseudonymised Census of Population Analysis (COPA) 2016 data set. This report presents a statistical overview of the economic and social statistics of the linked 178,620 individuals only. The analysis compares the profile of confirmed cases across the first three waves of the pandemic in Ireland. The dates of each wave are based on HPSC methodology and reporting (https://www.hpsc.ie/a-z/respiratory/coronavirus/novelcoronavirus/surveillance/).  In wave 1 (from 1 March 2020 to 1 August 2020), the total number of cases in CIDR was 27,036 of which 18,279 (68%) were matched to COPA. In wave 2 (from 2 August 2020 to 21 November 2020), the total number of cases in CIDR was 43,934 of which 30,818 (70%) were matched to COPA. Finally, in wave 3 (from 22 November to 12 May 2021), the total number of cases in CIDR was 183,043 of which 129,523 (71%) were matched to COPA. Changes to the testing regime over the period could be expected to impact positive test numbers in the three waves. As well as the strict legal protections set out in the Statistics Act, 1993, and other existing regulations, we are committed to protecting individual privacy and all identifiable information from each of the data sources used in our analysis, such as name, date of birth and addresses, are removed before use and only anonymised statistical aggregates are produced. For further information on the data sources, linking procedures and limitations of this report, see Methodology.

The age and gender of the 178,620 confirmed COVID-19 cases in this study are compared with the 254,013 COVID-19 cases which were in the CIDR database on 12 May 2021 in Figure 1.

Demographic Profile of COVID-19 Cases by Wave

• People with COVID-19 are more likely to be female, with the largest difference in wave 1 when 54% of cases were female

• The proportion of cases which were aged 0-14 and 15-24 increased dramatically between wave 1 and 2 and then dropped slightly in wave 3. The opposite pattern can be seen for people aged 65 and over, who made up 26% of cases in wave 1 but just 9% in wave 2 and 11% in wave 3.

• Dublin accounted for over 50% of cases in wave 1 but just 31% and 35% in waves 2 and 3. The percentage of cases increased between waves 1 and 2 in Cork, Donegal, Galway, Limerick, Meath and Wexford. The proportions in all other counties remained consistent during each of the waves.

The key findings of this report are:

• In wave three, 89% of cases were Irish nationals, 86% were white Irish and 85% were born in Ireland
• Overcrowded homes, where there is more than one person per room, accounted for 8% of households with a confirmed case in wave three compared to 19% in wave one
• In wave one, 86% of matched cases said they were in good or very good general health in Census 2016 compared with 91% in wave three
• Nurses and Midwives was the most common occupation of COVID-19 cases in wave one but the most common occupation to contract COVID-19 in waves two and three were Sales and Retail Assistants, Cashiers and Checkout Operators
• Employees in the Health and Social Work sector were hardest hit in the early months of the COVID-19 pandemic, making up 60% of cases amongst those employed in April 2020
• In wave one, higher standardised incidence rates were found in less deprived areas than in more deprived areas, but this reversed in the second wave, while in wave three rates were consistent across deprivation areas

This report is an example of the policy-relevant research projects the CSO are developing as part of its leadership role in the Irish Statistical System. Our goal is to maximise the variety and volume of data available to provide high quality information to the Government, businesses and citizens, through the development of a National Data Infrastructure (NDI).

The NDI plays an integral part in facilitating the CSO to develop new and improved statistical products for the benefit of citizens and policymakers. The core concept of the NDI involves the collection, maintenance and storage on all public sector data holdings, of the associated PPSN, Eircode and Unique Business Identifier (UBI) to be developed whenever they are relevant to Public Sector Body transactions with customers. This supports the development of targeted policy interventions.

Under the auspices of the Statistics Act 1993, and in compliance with all relevant data protection legislation, the CSO is in a unique position to gather and link administrative data sources held by Government departments and agencies and evaluate their potential for statistical use.