Impact of Long SARS-CoV-2 Omicron on Health Care burden. Comparative with the Pre-Omicron waves. A Case Control Study (Preprint)

Abstract

BACKGROUND The global population has been profoundly affected by the SARS-CoV-2 pandemic, resulting in elevated morbidity and mortality. Following the initial acute phase of illness, healthcare resource utilization has escalated among individuals with SARS-CoV-2 infection, attributed to persistent symptoms or the emergence of new illnesses. OBJECTIVE The primary aim of this study was to ascertain the enduring consequences of SARS-CoV-2 virus infection on both the incidence of new diagnoses and the utilization of healthcare resources among patients, within the context of the Omicron pandemic. A case-control investigation was conducted with the aim of drawing comparisons between the Omicron wave and the preceding pre-Omicron waves. METHODS This matched retrospective cohort study included patients of all ages from two healthcare Departments. Patients were matched on control and were followed-up for 6 months after SARS-CoV-2 infection. Previous vaccination, new diagnosis (CIE10) and use of health care resources were recorded. RESULTS In the study, a total of 41,577 patients with a history of prior COVID infection were included, alongside an equivalent number of controls. This cohort encompassed 33,249 adults aged >17 years and 8,328 youths aged <18 years. Notably, our analysis revealed the identification of forty new diagnoses. The incidence rate per 100 patients over a six-month period stood at 27.2 for vaccinated and 25.1 for unvaccinated adults (p=0.09), while among youths, the corresponding rates were 25.7 for vaccinated and 36.7 for unvaccinated individuals (P<001). Overall, the incidence of new diagnoses was notably higher in patients when compared to controls. Additionally, vaccinated patients exhibited a reduced incidence of new diagnoses, particularly among women (P<001) and younger patients (P<001), irrespective of the number of vaccine doses administered and the duration since the last dose. Furthermore, an increase in the utilization of healthcare resources was observed in both adult and adolescent patients, albeit with lower figures noted in vaccinated individuals. In the comparative analysis between the Pre-Omicron and Omicron waves, the incidence of new diagnoses was higher in the former; however, distinct patterns of diagnosis were evident. Similarly, healthcare resource utilization, encompassing primary care, specialist, and emergency services, was more pronounced in the Pre-Omicron wave. CONCLUSIONS The rise in new diagnoses following SARS-CoV-2 infection warrants attention due to its potential implications for health systems, which may necessitate the allocation of supplementary resources. The absence of vaccination protection presents a challenge to the healthcare system.