Clinical and laboratory features of COVID-19 in the vaccinated patients and the patients after previous illness

Abstract

Abstract: patients with COVID-19 can have a wide range of clinical manifestations: from generalized intoxication and respiratory symptoms to complaints from other organs and systems. The severity of the disease primarily depends on the age of the patients, the presence of comorbidities, and the susceptibility of the body to a particular variant of the SARS-CoV-2 virus. Vaccination and pre-infection provide a period of immune protection against reinfection. However, it has been reported that patients who have been vaccinated or have had COVID-19 can get sick in the same way as nonimmune individuals. The aim of our study was to analyze and compare clinical and laboratory features of the course of coronavirus disease 2019 among hospitalized vaccinated patients who contracted COVID-19 for the first time and hospitalized unvaccinated patients who had previously contracted COVID-19, which was confirmed by laboratory tests. The study included 220 hospitalized patients who were divided into two groups: vaccinated patients who had no history of confirmed COVID-19 (n=129) and unvaccinated patients who had previously contracted COVID-19 (n=91). Results: unvaccinated patients who had history of confirmed COVID-19 had a more pronounced clinical picture of the disease; absolute lymphopenia was significantly more common in patients with severe and critical course in both study groups (p=0,0001); mean C-reactive protein values were statistically significantly different between patients of both groups with moderate, severe and critical course of COVID-19, and were the highest ones in patients with critical course who died (p=0,0001).