Differences in clinical and laboratory characteristics in patients infected with COVID-19 during different epidemic waves

Abstract

Introduction/Aim: So far, the COVID-19 pandemic has seen four major epidemic waves that have affected more than 753 million people. Epidemiological studies have confirmed variability of clinical presentation of SARS-CoV-2 infection in these epidemic waves. During this period, virus mutations have contributed to greater challenges regarding treatment and prevention. The aim of the study is to determine the differences in clinical presentation, laboratory parameters, as well as the treatment outcome of patients suffering from COVID-19 during four different epidemic waves caused by different genotypic and phenotypic variants of SARS-CoV-2. Material and Methods: We conducted retrospective study in which data were collected from hospitalized patients at the University Clinical Centre of Serbia Clinic for Infectious and Tropical Diseases in the period between March 1, 2020 and December 1, 2021. Statistical analyses, socio-epidemiological, clinical, radiographic and laboratory characteristics of patients through different epidemic waves of COVID-19 were compared. Results: The study included 523 patients. Elevated body temperature was the first and the most common symptom of COVID-19 infection in all 4 epidemic waves, whereas cough and malaise were most common symptoms in the fourth wave. Cough was second most common symptom in third wave (p<0.05), following elevated body temperature, whereas malaise was second most common in the second wave. Diarrhea and nausea were significantly more common in the fourth wave compared to the previous waves (p=0.04 and p=0.02). Conclusion: Highest values of inflammatory biomarkers were found in the second and the fourth wave. The fourth wave was characterized by the largest number of hospitalized patients, and it represented the peak of the pandemic. Treatment options varied through the waves, and corticosteroid use was most common during the fourth epidemic wave in hospital conditions.