Quantifying the impact of regional variations in COVID-19 infections and hospitalisations across Ireland

Roe, M; Wall, P; Mallon, P; Sundaram, D; Kumawat, J; Horgan, M

BACKGROUND: As most COVID-19 transmission occurs locally, targeted measures where the likelihood of infection and hospitalisation may be a prudent risk management strategy. To date, in the Republic of Ireland, a regional comparison of COVID-19 cases and hospitalisations has not been completed. Here we investigate (1) the variation in rates of confirmed infection and hospital admissions within geographical units of the Republic of Ireland, and (2) frequency of deviations in risk of infection or risk of hospitalisation. METHODS: We analysed routinely-collected, publicly-available data available from the national Health Protection and Surveillance Centre (HPSC) and Health Service Executive (HSE) from nine geographical units, known as Community Health Organisation (CHO) areas. The observational period included 206 14-day periods (1 Sept 2020 - 15 Apr 2021). RESULTS: A total of 206,844 laboratory confirmed cases and 7,721 hospitalisations were reported. The national incidence of confirmed infections 4508 (95% CI 4489-4528) per 100,000 people. The risk of hospital admission among confirmed cases was 3.7% (95% CI 3.5-3.9). Across geographical units, the likelihood that rolling 14-day risk of infection or hospitalisation exceeded national levels was 9-86% and 0-88%, respectively. In the most affected regions, we estimate this resulted in an excess of 15,180 infections and 1,920 hospitalisations. CONCLUSIONS: Responses to future COVID-19 outbreaks should consider the risk and harm of infection posed to people living in specific regions. Given the recent surges of COVID-19 cases in Europe, every effort should be made to strengthen local surveillance and to tailor community-centered measures to control transmission.