Background/Objectives: The aim of this analysis of data from the multi-year nationwide SARSTer program in Poland was to compare the clinical presentation and course of COVID-19 in the last two infectious seasons. Methods: Clinical data from 719 consecutive patients hospitalized between April 2023 and March 2024 were compared with data from 360 patients hospitalized between 1 April 2024 and 31 March 2025. Results: In the 2023/2024 season, hospitalizations due to COVID-19 occurred primarily between September and January, and in the 2024/2025 season, the majority of hospitalizations occurred between July and November. In the 2024/2025 season, we documented a change in the age structure, with an increasing predominance of hospitalized patients over 70 years of age (68% vs. 60% in 2023/2024), a milder disease manifestation, reflected in a significantly lower percentage of patients with pulmonary lesions (19% vs. 24%), an improvement in the clinical course of the disease, reflected in a halving of the number of hospitalizations, a significantly higher percentage of patients with clinical improvement in subsequent weeks of hospitalization, including those discharged from the hospital within the first week (39% vs. 30%), and a significantly lower mortality rate (4.7% vs. 7.9%), especially among patients over 70 years of age (5.4% vs. 10.4%). This indicates that the trend of a milder disease course initiated by the emergence of the Omicron variant continues. Conclusions: In conclusion, our findings provide real-world clinical evidence of the evolution of the COVID-19 situation in the post-pandemic era.

This study aimed to analyze the differences in severity and clinical characteristics of COVID-19 in infants hospitalized in Poland in 2021, when the dominance of variants of concern (VOCs) alpha and delta was reported, compared to 2020, when original (wild) SARS-CoV-2 was dominant (III–IV vs. I–II waves of the pandemic, respectively). In addition, the influence of the presence of comorbidities on the clinical course of COVID-19 in infants was studied. This multicenter study, based on the pediatric part of the national SARSTer database (SARSTer-PED), included 940 infants with COVID-19 diagnosed between March 1, 2020, and December 31, 2021, from 13 Polish inpatient centers. An electronic questionnaire, which addressed epidemiological and clinical data, was used. The number of hospitalized infants was significantly higher in 2021 than in 2020 (651 vs. 289, respectively). The analysis showed similar lengths of infant hospitalization in 2020 and 2021, but significantly more children were hospitalized for more than 7 days in 2020 (p < 0.009). In both analyzed periods, the most common route of infection for infants was household contact. There was an increase in the percentage of comorbidities, especially prematurity, in children hospitalized in 2021 compared to 2020. Among the clinical manifestations, fever was predominant among children hospitalized in 2021 and 2020. Cough, runny nose, and loss of appetite were significantly more frequently observed in 2021 (p < 0.0001). Severe and critical conditions were significantly more common among children with comorbidities. More infants were hospitalized during the period of VOCs dominance, especially the delta variant, compared to the period of wild strain dominance, even though indications for hospitalization did not include asymptomatic patients during that period. The course of COVID-19 was mostly mild, characterized mainly by fever and respiratory symptoms. Comorbidities, particularly from the cardiovascular system and prematurity, were associated with a more severe course of the disease in infants.

Metallomics, which studies the role of metals in biological processes, is crucial for understanding the impact of elements on human health. It requires an integrated approach combining quantitative and functional methods, supported by advanced analytical techniques. A comprehensive understanding of metallomics considers the accumulation, speciation, and distribution of metals. In recent decades, an increasing number of studies have focused on determining metal levels in human tissues, particularly in the context of chronic diseases and developmental disorders. Levels of macro- and microelements, both essential and toxic, play a fundamental role in both physiological and pathological processes. Given the increasing health risks associated with addictions such as smoking, understanding the mechanisms of toxicity based on metallomic studies is crucial. This literature review synthesizes current advances in analytical techniques used to determine trace elements in biological samples, the accumulation of toxic metals, and the disruption of element homeostasis in tobacco smokers. The aim of this study is to identify key risks from tobacco-related metal exposure, thereby providing a deeper understanding of the long-term health consequences. The obtained results may constitute the basis for future directions of metallomic research.