Differential Inflammatory Responses in Adult and Pediatric COVID-19 Patients: Implications for Long-Term Consequences and Anti-Inflammatory Treatment.

BACKGROUND COVID-19 manifests with varying degrees of severity across different age groups; adults typically experience more severe symptoms than children. Matrix metalloproteinases (MMPs), known for their role in tissue remodeling and immune responses, may contribute to the pathophysiological disparities observed between these groups. We sought to delineate differences in serum MMP profiles between adult and pediatric COVID-19 patients, assess the influence of anti-inflammatory treatment on MMP levels, and examine potential implications for long-term consequences. MATERIAL AND METHODS Serum samples from adult and pediatric COVID-19 patients, alongside controls, were analyzed for MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-10, MMP-12, MMP-13, EMMPRIN, TNF-alpha, TIMP-1, TIMP-2, TIMP-3, and TIMP-4. A subset of adult patients received treatment with glucocorticoids, tocilizumab, and convalescent plasma, and MMP levels were compared with those of untreated patients. RESULTS Elevated levels of MMP-1, MMP-7, TIMP-1, and TIMP-2 were observed in adult and pediatric patients. Adult patients displayed higher concentrations of MMP-3, MMP-8, MMP-9, TNF-alpha, and TIMP-4 than children. Post-treatment reduction in MMP-1, MMP-8, MMP-9 levels was observed, with median decreases from 21% to 70%. MMP-3 and MMP-7 remained largely unchanged, and MMP-2 concentrations increased after treatment. Notably, anti-inflammatory treatment correlated with reduced post-treatment MMP levels, suggesting potential therapeutic benefit. CONCLUSIONS Distinctive inflammatory responses in COVID-19 were evident between adults and children. While certain MMPs exhibited post-treatment reduction, the persistence of elevated levels raises concerns about potential long-term consequences, including lung fibrosis. Our findings emphasize the need for personalized treatment strategies and further investigation into the dynamics of MMP regulation in COVID-19.

Clinical Presentation and Co-Detection of Respiratory Pathogens in Children Under 5 Years with Non-COVID-19 Bacterial and Viral Respiratory Tract Infections: A Prospective Study in Bialystok, Poland (2021-2022).

BACKGROUND Respiratory tract infections (RTIs) in children often involve a complex interplay between viruses and bacteria. This study aimed to evaluate clinical presentation in children under 5 years old diagnosed with non-COVID-19 bacterial and viral respiratory tract co-infections between October 2021 and May 2022 in Bialystok, Poland. MATERIAL AND METHODS We recruited 100 children under 5 years with RTIs who tested negative for SARS-CoV-2. Nasopharyngeal swabs were screened for 19 viruses and 7 bacterial strains using molecular assays. RESULTS Viral pathogens were detected in 71% of patients and bacterial pathogens were detected in 59%. The most common pathogens were Haemophilus influenzae (n=48), rhinoviruses (n=32), and Streptococcus pneumoniae (n=30). Single pathogens were detected in 36%, dual in 37%, triple in 15%, and quadruple in 2%. Bacterial pathogens were co-detected with viruses in 40 cases, mostly with rhinoviruses (n=15). Two different viruses were found in 14 children and the most common co-detection was adenovirus with rhinovirus (n=5); dyspnea (63% vs 11%) and wheezing (75% vs 22%) were more common in children with human bocavirus. Fever was a common symptom in children with human adenovirus (88% vs 58%). Detection of bacteria and multiple detections were more common in day-care attendees, but were not associated with clinical picture of RTI. CONCLUSIONS Consistent with previous studies, we found a high prevalence of rhinoviruses, despite ongoing implementation of non-pharmaceutical interventions to contain the COVID-19 pandemic. Co-detection of 2 different respiratory pathogens was frequent, but we found no evidence that this was associated with the severity of infections.

The Role of Adipokines in the Pathologies of the Central Nervous System.

Adipokines are protein hormones secreted by adipose tissue in response to disruptions in physiological homeostasis within the body's systems. The regulatory functions of adipokines within the central nervous system (CNS) are multifaceted and intricate, and they have been identified in a number of pathologies. Therefore, specific adipokines have the potential to be used as biomarkers for screening purposes in neurological dysfunctions. The systematic review presented herein focuses on the analysis of the functions of various adipokines in the pathogenesis of CNS diseases. Thirteen proteins were selected for analysis through scientific databases. It was found that these proteins can be identified within the cerebrospinal fluid either by their ability to modify their molecular complex and cross the blood-brain barrier or by being endogenously produced within the CNS itself. As a result, this can correlate with their measurability during pathological processes, including Alzheimer's disease, amyotrophic lateral sclerosis, multiple sclerosis, depression, or brain tumors.

The Detectability of the Viral RNA in Blood and Cerebrospinal Fluid of Patients with Tick-Borne Encephalitis.

BACKGROUND: The detection rate of viral RNA in tick-borne encephalitis (TBE) is low and variable between studies, and its diagnostic/prognostic potential is not well defined. We attempted to detect RNA of TBE virus (TBEV) in body fluids of TBE patients. METHODS: We studied 98 adults and 12 children with TBEV infection, stratified by the disease phase and presentation. EDTA blood and cerebrospinal fluid (CSF) samples were obtained upon hospital admission. RNA was extracted from freshly obtained plasma, concentrated leukocyte-enriched CSF, and whole blood samples, and real time PCR was performed with a Rotor-Gene Q thermocycler. RESULTS: TBEV RNA was detected in (1) plasma of one (of the two studied) adult patients with an abortive infection, (2) plasma of two (of the two studied) adults in the peripheral phase of TBE, and (3) plasma and blood of an adult in the neurologic phase of TBE presenting as meningoencephalomyelitis. No CSF samples were TBEV RNA-positive. CONCLUSIONS: The detection of TBEV RNA in blood might be diagnostic in the peripheral phase of TBE. The lack of TBEV RNA in the CSF cellular fraction speaks against TBEV influx into the central nervous system with infiltrating leukocytes and is consistent with a relatively low intrathecal viral burden.

Comparison of the interleukin 27 expression for the acute and chronic phase of mononucleosis in children.

BACKGROUND: The objective of the current study was to assess the serum level of interleukin 27 in children with mononucleosis and to compare the expression of this cytokine in the acute and chronic phase of the infection. METHODS: The level of IL-27 was determined using commercial enzyme-linked immunosorbent assay (ELISA) kits (Diaclone SAS, Besancon, France). Other laboratory findings were determined using routine laboratory methods. RESULTS: Serum level of IL-27 was found to be significantly higher in children with mononucleosis in comparison with healthy subjects (almost a 4-fold increase, 15.7 vs. 4.2 pg/mL, p < 0.001). It was also significantly higher in the acute phase compared to the chronic stage of the disease (more than a two-fold increase, 20.7 vs. 9.64 pg/mL, p < 0.001). This cytokine positively correlated with ALT, AST, LDH activity and WBC count (R = 0.498, p < 0.001; R = 0.586, p < 0.001; R = 0.170, p < 0.05, R = 0.329, p < 0.05, respectively) in the whole study, and only with AST activity in the chronic phase subgroup (R = 0.684, p < 0.05). CONCLUSION: In conclusion, this study shows that serum concentration of interleukin 27 in children with mononucleosis is increased, thus confirming the on-going inflammatory process. We also suggest that IL-27 can be a useful indicator to differentiate between the acute and chronic phase of the disease.

Epidemiology of tick-borne encephalitis in Poland (2010-2019) and the impact of the COVID-19 pandemic on the notified incidence of the disease.

INTRODUCTION: Tick-borne encephalitis (TBE) is endemic in many parts of Eurasia including countries previously considered to be free from the disease. The incidence of TBE is changing owing to various ecological and climatic factors. The factors influencing the variability of the number of TBE cases are still under investigation. In 2020 the new coronavirus SARS-CoV-2 emerged causing COVID-19 pandemic. Governments have reorganized health care systems to contain a surge of COVID-19 cases and avoid hospital overload. Moreover, new measures have modified several aspects of social habits leading to a change in the incidence of numerous diseases. We aimed to evaluate the epidemiology of TBE in the last decade (2010-2019) and to demonstrate the impact of the surge of SARS-CoV-2 infections on the TBE incidence as reported to a national surveillance database. MATERIAL AND METHODS: We performed the analysis of the TBE notification from the epidemiologic reports in the years 2010-2019 and in the pandemic year 2020 at a national and regional level in Poland. We included data from two infectious disease departments located in the most TBE-prevalent province of Poland. RESULTS: Most cases of TBE occur in two provinces of Northeastern Poland from May to December. The increasing temporal trend occurred in Poland in 2016-2017. The increased number of cases of COVID-19 coincided with a reduction of the number of the reported TBE cases in 2020. CONCLUSIONS: Tick-borne encephalitis virus activity in Poland is invariably concentrated in endemic regions of Northeastern Poland fluctuating considerably from year to year. The decrease of TBE incidence with surge of COVID-19 patients conceivably resulted from underreporting due to limited access to specialized diagnostics. In endemic areas, TBE should be included in the differential diagnostics in all the cases when the central nervous system infection in suspected.

Challenges and new methods in the diagnosis of Lyme disease in children.

Despite the constant development of biotechnology, laboratory diagnostics of Lyme disease in children still poses a significant challenge. The aim of this article is to present the current methods of Lyme disease diagnosis and its future perspectives. A serological test is often the first step in supporting clinical diagnosis of Lyme disease in children. Recently, a new generation of enzyme-linked immunosorbent assays has been created. These assays use recombinant proteins or synthetic peptides in their antigenic spectrum. It is postulated that these tests may replace the classic immunoblot as the second step in the Lyme disease diagnostic protocol. Direct detection methods based on bacterial culture techniques or using the polymerase chain reaction (PCR) have inadequate sensitivity, which prevents their widespread use in clinical practice. Recently, a number of other tools have been developed that are of supportive importance. Among them, measuring of the CXCL13 chemokine concentration in the cerebrospinal fluid has the potential to become a routine procedure in the diagnosis of Lyme disease in children. Future diagnostic strategies of Lyme disease might include: innovative immunological tests using new antigens, combining serology with direct methods in order to increase sensitivity, standardization of selected unconventional tests, identification of host response biochemical metabolic markers or linking clinical symptoms reported by patients with appropriate test panels. In the absence a vaccine which protects against the disease, the preventive recommendations given to parents to prevent tick bites in children remain valid.

Tick-borne encephalitis - a review of current epidemiology, clinical symptoms, management and prevention.

Tick-borne encephalitis virus (TBEV), which causes central nervous system infections, is a major health problem in Europe and Asia. This virus is transmitted mainly via the bite of a tick. However, an infection may also occur as a result of consuming raw milk. In 2018, a total of 3 092 cases of tick-borne encephalitis (TBE) were reported in EU countries. In recent years, TBE has emerged in previously unaffected regions; thus, new endemic areas have been identified. Most cases of TBE occur in spring and autumn, which correlates with increased tick activity. TBE is found in all age groups, including infants. The clinical presentation of TBE varies, but the severity of the infection and risk of complications increase with age. Post-encephalitic syndrome, which affects up to 50% of infected individuals, significantly reduces quality of life. Currently, there is no effective treatment for TBE, and supportive management is used in the acute phase of the disease. Therefore, anti-TBE immunization and the avoidance of tick bites are of key importance in preventing this infection.

Plasma concentration and expression of adipokines in epicardial and subcutaneous adipose tissue are associated with impaired left ventricular filling pattern.

BACKGROUND: Adipokines in serum derive mainly from subcutaneous and visceral adipose tissues. Epicardial adipose tissue (EAT), being a relatively small but unique fat depot, probably does not make an important contribution to systemic concentrations of adipokines. However, proximity of EAT to cardiac muscle and coronary arteries allows cells and proteins to penetrate between tissues. It is hypothesized that overexpression of proinflammatory cytokines in EAT plays an important role in pathophysiology of the heart. The aim of the study was to analyze the relationship between echocardiographic heart parameters and adipokines in plasma, epicardial, and subcutaneous fat in patients with obesity and type 2 diabetes mellitus (T2DM). Additionally, we evaluate proinflammatory properties of EAT by comparing that depot with subcutaneous adipose tissue. METHODS: The study included 55 male individuals diagnosed with coronary artery disease (CAD) who underwent planned coronary artery bypass graft. Plasma concentrations of leptin, adiponectin, resistin, visfatin, apelin, IL-6, and TNF-α, as well as their mRNA and protein expressions in EAT and subcutaneous adipose tissue (SAT) were determined. RESULTS: Obesity and diabetes were associated with increased leptin and decreased adiponectin plasma levels, higher protein expression of leptin and IL-6 in SAT, and higher visfatin protein expression in EAT. Impaired left ventricular (LV) diastolic function was associated with increased plasma concentrations of leptin, resistin, IL-6, and adiponectin, as well as with increased expressions of resistin, apelin, and adiponectin in SAT, and leptin in EAT. CONCLUSIONS: Obesity and T2DM in individuals with CAD have a limited effect on adipokines. Expression of adipokines in EAT and SAT is linked to certain heart parameters, however diastolic dysfunction of the LV is strongly associated with circulating adipokines.

Enteroviral meningitis reduces CSF concentration of Aß42, but does not affect markers of parenchymal damage.

Biomarkers classically studied in Alzheimer's disease have been analyzed in numerous central nervous system infections in adults, but there are scarce data on these biomarkers in children. Enteroviruses appear to be the most common cause of aseptic meningitis throughout the world. The aim of the study was to investigate neuroinflammatory properties of non-polio enteroviruses by measuring CSF concentrations of biomarkers that are involved in neuropathological pathways of neurodegenerative disorders. We measured Aß42, t-tau, and S100B concentrations in 42 children with enteroviral meningitis (EM) compared to control group without central nervous system infection. We found enteroviral meningitis (EM) to reduce CSF concentration of Aß42 (median, 1051.1 pg/mL; interquartile range (IQR), 737.6-1559.5 vs. median, 459.4 pg/mL; IQR, 312.0-662.0, p < 0.001). In contrast, CSF concentrations of t-tau and S100B were not affected by EM. There was a correlation between total neutrophil count in CSF and Aß42 (R = - 0.59, p < 0.001). Absolute number of mononuclear cells in the CSF correlated with CSF t-tau (R = 0.41, p < 0.05). Both correlations remained significant after adjustment for age, blood leukocytes, serum CRP, CSF leukocytes, and CSF protein concentration.

Toxocarosis in children: poor hygiene habits and contact with dogs is related to longer treatment.

The objective of this study was to investigate the main clinical signs and symptoms of toxocarosis in children and the treatment results. The study group consisted of 66 seropositive children aged 2 to 16 years, evaluated in an outpatient clinic in north-eastern Poland for 24 months. Male gender and living in urban areas predominated in the study population. Children presented with non-specific symptoms, of which the most common was abdominal pain or tenderness, which was reported by 39 (59%) patients. Absolute eosinophil counts were increased in 32 (48%) children. Total IgE concentrations were increased in 31 of 55 (56%) tested children. All evaluated children received albendazole as a first-line treatment. In 19 cases, additional treatment with albendazole and/or diethylcarbamazine was provided. The analysis of possible causes of prolonged treatment revealed that significant risk factors were geophagia [odds ratio (OR), 6.3; 95% confidence interval (95% CI), 1.8-21.8; p < 0.01] and daily contact with a dog [OR, 5.9; 95% CI, 1.3-27.3, p < 0.05]. We hypothesise that poor hygiene habits and daily contact with a dog pose a risk of reinfection and limits treatment efficiency. Because of non-specific signs and frequent lack of eosinophilia, physicians should maintain high levels of suspicion for toxocarosis, particularly in patients who live in regions heavily contaminated with Toxocara eggs.

Environmental contamination with Toxocara eggs and seroprevalence of toxocariasis in children of northeastern Poland.

Toxocariasis is a worldwide distributed zoonotic disease. Soil contaminated with Toxocara eggs appears to be the main source of infection for humans. The aim of our study was to estimate the environmental contamination with Toxocara eggs in public areas in northeastern Poland followed by the assessment of seroprevalence of toxocariasis in the children's population inhabiting the areas. A total of 168 soil samples were collected in June and September from public areas, and 28 from patients' residences. They were all examined for Toxocara eggs using the centrifugal flotation technique. Two-step serological tests comprising enzyme-linked immunosorbent assay (ELISA) and Western blot (WB) were performed in 190 children aged 2-17 without any symptoms of toxocariasis. The positive samples accounted for 36 and 32 % in the urban area, 39 and 18 % in the suburbs, and 39 and 46 % in parks, for June and September, respectively. All the sites located near the patients' residences with confirmed persistent toxocariasis were found contaminated with Toxocara eggs. A significant drop in the mean number of eggs was noted in the suburbs after summer (0.64 vs 0.18, p < 0.05). High and constant contamination was documented in soil from urban sandboxes and parks. The overall seroprevalence in children tested for toxocariasis was 4.2 % as determined by ELISA and WB (3.0 % in preschool children and 7.7 % in school children). The current study revealed high contamination of public areas in northeastern Poland with Toxocara eggs as well as marked seroprevalence in asymptomatic children. There is an urgent need to introduce and promote preventive health measures to limit spread of toxocariasis.

Attitudes towards the Tick-Borne Encephalitis Vaccine among Children's Guardians: A Cross-Sectional Survey Study in Poland.

This cross-sectional survey study aimed to assess the attitudes and knowledge of children's guardians in Poland towards tick-borne encephalitis (TBE) and its vaccine, as well as to compare these attitudes to those regarding other infectious diseases and their vaccines. Data were collected through anonymous questionnaires, both paper-based and online, from 3030 respondents across Poland, with the majority being from TBE-endemic areas. The survey included questions on demographic characteristics, general vaccination beliefs, and specific perceptions of TBE and its vaccine. Statistical analysis revealed significant associations between willingness to vaccinate against TBE and factors such as general vaccination attitudes, information sources, vaccine safety ratings, and perceptions of disease severity. Results indicated that guardians from larger cities and those with fewer children were more likely to vaccinate. Additionally, parents who supported general vaccinations were significantly more willing to vaccinate against TBE. The study concludes that enhancing public awareness about the safety and importance of the TBE vaccine, especially in endemic regions, is crucial for improving vaccination rates. Targeted public health interventions addressing misconceptions and providing accurate information are essential strategies to increase TBE vaccine uptake and protect children from this serious disease.

Intensified Circulation of Echovirus 11 after the COVID-19 Pandemic in Poland: Detection of a Highly Pathogenic Virus Variant.

After the first phase of the COVID-19 pandemic in Europe, a new highly pathogenic variant of echovirus 11 (E11) was detected. The aim of this study was to analyze the genetic diversity of Polish E11 environmental and clinical strains circulating between 2017 and 2023 as well as compare them with E11 strains isolated from severe neonatal sepsis cases reported in Europe between 2022 and 2023. Additionally, the study explores the effectiveness of environmental monitoring in tracking the spread of new variants. For this purpose, the complete sequences of the VP1 capsid protein gene were determined for 266 E11 strains isolated in Poland from 2017 to 2023, and phylogenetic analysis was performed. In the years 2017-2023, a significant increase in the detection of E11 strains was observed in both environmental and clinical samples in Poland. The Polish E11 strains represented three different genotypes, C3, D5 and E, and were characterized by a high diversity. In Poland, the intensive circulation of the new variant E11, responsible for severe neonatal infections with a high mortality in Europe, was detected in the years 2022-2023. This investigation demonstrates the important role of environmental surveillance in the tracking of enteroviruses circulation, especially in settings with limited clinical surveillance.

[Epicardial adipose tissue and its role in cardiac physiology and disease]. / Tkanka tluszczowa nasierdziowa. Znaczenie fizjologiczne oraz rola w patofizjologii chorób serca.

Adipose tissue secretes a number of cytokines, referred to as adipokines. Intensive studies conducted over the last two decades showed that adipokines exert broad effects on cardiac metabolism and function. In addition, the available data strongly suggests that these cytokines play an important role in development of cardiovascular diseases. Epicardial adipose tissue (EAT) has special properties that distinguish it from other deposits of visceral fat. Overall, there appears to be a close functional and anatomic relationship between the EAT and the cardiac muscle. They share the same coronary blood supply, and there is no structure separating the adipose tissue from the myocardium or coronary arteries. The role of EAT in osierdziocardiac physiology remains unclear. Its putative functions include buffering coronary arteries against the torsion induced by the arterial pulse wave and cardiac contraction, regulating fatty acid homeostasis in the coronary microcirculation, thermogenesis, and neuroprotection of the cardiac autonomic ganglia and nerves. Obesity (particularly the abdominal phenotype) leads to elevated EAT content, and the available data suggests that high amount of this fat depot is associated with increased risk of ischemic heart disease, cardiac hypertrophy and diastolic dysfunction. The mass of EAT is small compared to other fat deposits in the body. Nevertheless, its close anatomic relationship to the heart suggests that this organ is highly exposed to EAT-derived adipokines which makes this tissue a very promising area of research. In this paper we review the current knowledge on the role of EAT in cardiac physiology and development of heart disease.

Diagnostic Precision in Lyme borreliosis: Assessing VlsE and C6 Antigens in a Pediatric Cohort.

(1) Background: Lyme borreliosis (LB) is a tick-borne disease known for its diagnostic challenges. Conventional two-tiered testing (CTTT) for antibodies is time-consuming, has low sensitivity in the early stages of disease, and sometimes generates false-positive IgM immunoblots. To tackle this issue, modified two-tiered testing (MTTT) was introduced, incorporating recombinant VlsE and C6 antigens to enhance diagnostic accuracy. (2) Methods: In this prospective study, we enrolled children exhibiting symptoms indicative of LB. We collected serum samples at various intervals and subjected them to analysis using standard enzyme immunoassays. We then compared these results with the outcomes from the VlsE and C6 assays. (3) Results: In our study, all 33 patients displaying erythema migrans (EM), a characteristic symptom of LB, exhibited positive responses to the C6 antigen. This finding underscores the potential utility of the C6 antigen as a reliable diagnostic tool for LB. Additionally, we observed a significant reduction in anti-VlsE antibody levels following antibiotic treatment in EM patients. (4) Conclusions: The utilization of recombinant VlsE and C6 antigens in LB diagnostics and monitoring has yielded promising results. Nonetheless, it is imperative for clinicians to exercise caution and interpret results in conjunction with clinical findings, considering the dynamic nature of medical guidelines. Even with recombinant antigen tests, some children with EM tested negative, highlighting the importance of clinical diagnosis for treatment decisions. Furthermore, clinicians should be mindful of the possibility of persistently positive VlsE/C6 test results during LB treatment monitoring.

Associations of the cerebrospinal fluid lymphocyte population with a clinical presentation of tick-borne encephalitis.

In tick-borne encephalitis (TBE), lymphocytes infiltrating central nervous system are indispensable for the infection control, but also potentially immunopathogenic. To clarify their roles, we have evaluated cerebrospinal fluid (CSF) count of the main lymphocyte populations (considered as a proxy of the brain parenchyma lymphocytic infiltrate) in TBE patients and analyzed if they associate with clinical presentation, blood-brain barrier disruption and intrathecal antibody synthesis. We have studied CSF from 96 adults with TBE (50 with meningitis, 40 with meningoencephalitis, 6 with meningoencephalomyelitis), 17 children and adolescents with TBE and 27 adults with non-TBE lymphocytic meningitis. Th CD3+CD4+, Tc CD3+CD8+, double positive T CD3+CD4+CD8+, B CD19+ and NK CD16+/56+ cells were counted cytometrically with a commercial fluorochrome-stained monoclonal antibody set. The associations between the counts and fractions of these cells and clinical parameters were analyzed with non-parametric tests, p<0.05 considered significant. The TBE patients had lower pleocytosis with similar proportions of the lymphocyte populations compared to non-TBE meningitis. The different lymphocyte populations correlated positively with one another, as well as with CSF albumin, IgG and IgM quotients. The higher pleocytosis and expansion of Th, Tc and B cells associated with a more severe disease and neurologic involvement: Th with encephalopathy, myelitis and weakly with cerebellar syndrome, Tc with myelitis and weakly with encephalopathy, B with myelitis and with at least moderately severe encephalopathy. The double-positive T lymphocytes associated with myelitis, but not with other forms of CNS involvement. The fraction of double positive T cells decreased in encephalopathy and the fraction of NK in patients with neurologic deficits. In children with TBE, Tc and B counts were increased at the expense of Th lymphocytes in comparison with adults. The concerted intrathecal immune response, involving the main lymphocyte populations, increases with the clinical severity of TBE, with no evidently protective or pathogenic elements distinguishable. However, the particular populations including B, Th and Tc cells associate with different, though overlapping, spectra of CNS manifestations, suggesting they may be specifically related to TBE manifesting as myelitis, encephalopathy and cerebellitis. The double-positive T and NK cells do not expand evidently with severity and may be most closely associated with the protective anti-TBEV response.

The Influence of SARS-CoV-2 Variants B.1.1.7 and B.1.617.2 on a Different Clinical Course and Severity of COVID-19 in Children Hospitalized in 2021 Compared With 2020.

BACKGROUND: This study aimed to analyze the differences in the epidemiologic and clinical characteristics of coronavirus disease 2019 (COVID-19) in children hospitalized in 2021, when the severe acute respiratory syndrome coronavirus 2 variants B.1.1.7 (alpha) and B.1.617.2 (delta) dominated, compared with 2020. METHODS: In this multicenter study based on the pediatric part of the national SARSTer register (SARSTer-PED), we included 2771 children (0-18 years) with COVID-19 diagnosed between March 1, 2020, and December 31, 2021, from 14 Polish inpatient centers. An electronic questionnaire, which addressed epidemiologic and clinical data, was used. RESULTS: Children hospitalized in 2021 were younger compared with those reported in 2020 (mean 4.1 vs. 6.8 years, P = 0 .01). Underlying comorbidities were reported in 22% of the patients. The clinical course was usually mild (70%). A significant difference in the clinical course assessment between 2020 and 2021 was found, with more asymptomatic patients in 2020 and more severely ill children in 2021. In total, 5% of patients were severely or critically ill, including <3% of the participants in 2020 and 7% in 2021. The calculated mortality rate was 0.1% in general and 0.2% in 2021. CONCLUSION: Infections with severe acute respiratory syndrome coronavirus 2 variants alpha and delta lead to a more severe course of COVID-19 with more pronounced clinical presentation and higher fatality rates than infection with an original strain. Most of the children requiring hospitalization due to COVID-19 do not have underlying comorbidities.

Clinical Course and Severity of COVID-19 in 940 Infants with and without Comorbidities Hospitalized in 2020 and 2021: The Results of the National Multicenter Database SARSTer-PED.

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.

Amyloid and Tau Protein Concentrations in Children with Meningitis and Encephalitis.

Alzheimer's disease (AD) has emerged as a growing threat to human health. It is a multifactorial disorder, in which abnormal amyloid beta metabolism and neuroinflammation have been demonstrated to play a key role. Intrathecal inflammation can be triggered by infections and precede brain damage for years. We analyzed the influence of infections of the central nervous system on biomarkers that are crucially involved in AD pathology. Analyses of the cerebrospinal fluid (CSF) levels of Aß1-42, Aß1-40, Tau, and pTau proteins were performed in 53 children with neuroinfections of viral (n = 26) and bacterial origin (n = 19), and in controls (n = 8). We found no changes in CSF amyloid Aß1-42 concentrations, regardless of etiology. We showed an increase in tau and phosphorylated tau concentrations in purulent CNS infections of the brain, compared to other etiologies. Moreover, the total concentrations of tau in the CSF correlated with the CSF absolute number of neutrophils. These findings and the Aß 42/40 concentration quotient discrepancies in CFS between meningitis and encephalitis suggest that infections may affect the metabolism of AD biomarkers.