Surfing the Waves: Differences in Hospitalised COVID-19 Patients across 4 Variant Waves in a Belgian University Hospital

Abstract

The unprecedented COVID-19 pandemic took the form of successive variant waves, spreading across the globe. We wanted to investigate any shift in hospitalised patients’ profiles throughout the pandemic. For this study, we used a registry that collected data automatically from electronic patient health records. We compared clinical data and severity scores, using the National Institute of Health (NIH) severity scores, from all patients admitted for COVID-19 during four SARS-CoV-2 variant waves. Our study concluded that patients hospitalised for COVID-19 showed very different profiles across the four variant waves in Belgium. Patients were younger during the Alpha and Delta waves and frailer during the Omicron period. ‘Critical’ patients according to the NIH criteria formed the largest fraction among the Alpha wave patients (47.7%), while ‘severe’ patients formed the largest fraction among Omicron patients (61.6%). We discussed host factors, vaccination status, and other confounders to put this into perspective. High-quality real-life data remain crucial to inform stakeholders and policymakers that shifts in patients’ clinical profiles have an impact on clinical practice.

The impact of national and international travel on spatio-temporal transmission of SARS-CoV-2 in Belgium in 2021

“…During our study period, the Alpha variant was most prevalent over the largest part of the first half of 2021, while the Delta variant was dominant in the second half of the year. Although the Beta and Gamma variants were concomitantly identified over the first half of 2021, they did not play an important role in subsequent waves of SARS-CoV-2 variants observed in Belgium [ 30 , 49 ]. Furthermore, previous studies have shown that both the Alpha and Delta variants have 50%-70% higher transmissibility compared to the pre-existing variants, and they impacted individuals with similar demographic and comorbidity characteristics [ 49 , 50 ].…”

Distinct socioeconomic profile of patients hospitalised with severe COVID-19 and prepandemic respiratory infections in Brussels’s deprived areas: a case–control study

“…Another study has shown that the clinical characteristics of hospitalised patients with COVID-19 changed profoundly from one epidemic wave to the next but they do not analyse sociodemographic factors. 13 Meurisse et al, have also shown that more deprived municipalities were predicted to experience a higher COVID-19 incidence but this pattern of municipality-level socioeconomic inequalities was dependent on the period during the COVID-19 crisis. 14 Our study therefore focused on two Brussels university hospitals, CHU St Pierre and Érasme, located in the most deprived area of Brussels (for the former) and in a deprived area (for the latter).…”

“…However, this profile is comparable to the all-cause mortality gradient in non-pandemic times. Another study has shown that the clinical characteristics of hospitalised patients with COVID-19 changed profoundly from one epidemic wave to the next but they do not analyse sociodemographic factors 13. Meurisse et al , have also shown that more deprived municipalities were predicted to experience a higher COVID-19 incidence but this pattern of municipality-level socioeconomic inequalities was dependent on the period during the COVID-19 crisis 14…”

The Course of COVID-19 and Long COVID: Identifying Risk Factors among Patients Suffering from the Disease before and during the Omicron-Dominant Period

“…Available reports have documented a milder COVID-19 course caused by the Omicron variant, lower frequency of hospitalizations and admissions to intensive care units, as well as a decrease in the mortality rate compared to previous pandemic waves [ 16 , 17 , 18 ]. However, there is a need for studies assessing the clinical diversity of cases and effects of SARS-CoV-2 during the dominance of Omicron, which is responsible for the longest wave of the pandemic.…”