Changes in the utilisation of acute hospital care in Ireland during the first wave of the COVID-19 pandemic in 2020 [version 3; peer review: 2 approved, 1 approved with reservations]

Background: Reduced and delayed presentations for non-COVID-19 illness during the COVID-19 pandemic have implications for population health and health systems. The aim of this study is to quantify and characterise changes in acute hospital healthcare utilisation in Ireland during the first wave of COVID-19 to inform healthcare system planning and recovery. Methods: A retrospective, population-based, observational study was conducted using two national datasets, Patient Experience Time (PET) and Hospital In-Patient Enquiry (HIPE). The study period was 6th January to 5th July 2020. Results: Comparison between time periods pre- and post-onset of the COVID-19 pandemic within 2020 showed there were 81,712 fewer Emergency Department (ED) presentations (-18.8%), 19,692 fewer admissions from ED (-17.4%) and 210,357 fewer non-COVID-19 hospital admissions (-35.0%) than expected based on pre-COVID-19 activity. Reductions were greatest at the peak of population-level restrictions, at extremes of age and for elective admissions. In the period immediately following the first wave, acute hospital healthcare utilisation remained below pre-COVID-19 levels, however, there were increases in emergency alcohol-related admissions (Rate Ratio 1.22, 95% CI 1.03, 1.43, p-value 0.016), admissions with self-harm (Rate Ratio 1.39, 95% CI 1.01, 1.91, p-value 0.043) and mental health admissions (Rate Ratio 1.28, 95% CI 1.03, 1.60, p-value 0.028). Discussion: While public health implications of delayed and lost care will only become fully apparent over time, recovery planning must begin immediately. In the short-term, backlogs in care need to be managed and population health impacts of COVID-19 and associated restrictions, particularly in relation to mental health and alcohol, need to be addressed through strong public health and health system responses. In the long-term, COVID-19 highlights health system weakness and is an opportunity to progress health system reform to deliver a universal, high-quality, sustainable and resilient health system, capable of meeting population health needs and responding to future pandemics.</p

Immunocompromise among vaccinated versus unvaccinated COVID-19 cases admitted to critical care in Ireland, July to October 2021

As the COVID-19 pandemic progressed, so too did the proportion of cases admitted to critical care in Ireland who were fully vaccinated. Reporting of this observation has public health implications as incorrect interpretation may affect public confidence in COVID-19 vaccines. A potential explanation is the reduced ability of those who are immunocompromised to produce an adequate, sustained immune response to vaccination. We conducted an analysis of the association between COVID-19 vaccination status and underlying degree of immunocompromise among a cohort of critical care patients all with a confirmed diagnosis of COVID-19 admitted to critical care between July and October 2021. Multinomial logistic regression was used to estimate an odds ratio of immunocompromise among vaccinated COVID-19 cases in critical care compared to unvaccinated cases. In this study, we found a statistically significant association between the vaccination status of severe COVID-19 cases requiring critical care admission and underlying immunocompromise. Fully vaccinated patients were significantly more likely to be highly (OR = 19.3, 95 % CI 7.7-48.1) or moderately immunocompromised (OR = 9.6, 95 % CI 5.0-18.1) compared to unvaccinated patients with COVID-19. These findings support our hypothesis, that highly immunocompromised patients are less likely to produce an adequate and sustained immune response to COVID-19 vaccination, and are therefore more likely to require critical care admission for COVID-19 infection. </p