Introduction: The total number of confirmed cases of COVID-19 caused by the SARS-CoV-2 virus infection is over 621 million in the world. In approximately 63% of cases, the patient still experiences persistent symptoms 30 days after the onset of symptoms or hospitalisation, and 45.9% of patients have experienced or will experience symptoms for at least three months. Despite the prevalence of chronic symptoms and pathological changes that may affect gait and functional mobility in people with a history of COVID-19, there are few publications investigating the impact of these abnormalities. This study aims to determine the long-term effects of COVID-19 on gait and the Timed-Up and Go Task. Material and Methods: A total of 30 individuals took part in the experiment. The subjects in the study group were infected with the COVID-19 virus and required hospital treatment. Prior to the study, the subjects had no chronic diseases or other conditions affecting the musculoskeletal system. The non-infected by COVID-19 group was a healthy population with no history of COVID-19 disease. The study used the inertial system wireless motion analysis system based on 15 inertial sensors (inertial measurement units, IMUs). IMU sensors were placed on the following body segments: head, sternum, middle and lower spine, shoulder, arm, forearm, hand, shank, for the left and right limb. Movement task reports generated from the recording were created using myoRESEARCH 3.10. The subjects in the study group were asked to perform a movement task test—the Timed-Up and Go Test (TUG): sit-to-stand, walk (3 m) without change in direction, walk termination, and stand-to-sit. Results: It took 46% longer for those infected by COVID-19 (participants) to complete the entire movement task compared to those in the not-infected by COVID-19 group. Sit-to-Stand Time [s] was greater in the infected by COVID-19 group and was 2.1 ± 0.7. Mean Walking Speed [m/s] was lower than in the not-infected by COVID-19 group and was 0.26 ± 0.07. Walking cadence [steps/min] was lower and was 21.2 ± 1.2. Infected by COVID-19 participants achieved a smaller anterior pelvic tilt angle (p < 0.001) and a smaller hip flexion angle (p = 0.025), with an increase in knee (p < 0.001) and ankle (p < 0.001) flexion angles. Conclusions: Individuals in the infected by COVID-19 group present changes in the ranges of motion and the time to complete the TUG task, despite the fact that at least eight weeks passed after hospital discharge.

Vaccination is the best way to limit the extent of the COVID pandemic. Knowledge of the duration of the immune response will allow the planning of a vaccination protocol. This study aims to validate the complete (humoral and cellular) immune responses over time in large population groups following the full vaccination of healthcare professionals in real-life conditions and to assess the relationship between antibody levels and T-cell activity in relation to the characteristics of the study group. The samples for the study were obtained from volunteers (staff of two hospitals) on three occasions: before vaccination, T0, then 4–9 weeks after full vaccination (two doses BNT162b2), T1, and 7–9 months after vaccination, T2. The humoral response was investigated by the titre of anti-SARS-CoV-2 IgG antibodies to S1 protein. Assays were performed three times at intervals. The cellular response was assessed in a subgroup of 189 subjects by QuanT-Cell SARS-CoV-2 (IGRA). The assay was performed once. A group of 344 subjects fully vaccinated with the BNT162b2 vaccine were included in the study. The humoral response was observed in 100% of subjects at both 4–7 weeks and 7–9 months, but antibody titres fell by almost 90% in this interval. The cellular response was observed in 94% (177/189) of subjects 7–9 months after the second dose of vaccine. In subjects with a negative cellular response, eight out of 12 smoked. A factor associated with greater immunogenicity of vaccination was past SARS-CoV-2 infection. The administration of full BNT162b2 vaccination (two doses) induces humoral and cellular responses detectable even more than six months after vaccination. Smoking may be a factor associated with impaired cellular response to vaccination.

The total number of confirmed cases of COVID-19 caused by SARS-CoV-2 virus infection is over 621 million. Post-COVID-19 syndrome, also known as long COVID or long-haul COVID, refers to a persistent condition where individuals experience symptoms and health issues after the acute phase of COVID-19. The aim of this study was to assess the strength and fatigue of skeletal muscles in people recovered from COVID-19. A total of 94 individuals took part in this cross-sectional study, with 45 participants (referred to as the Post-COVID Cohort, PCC) and 49 healthy age-matched volunteers (Healthy Control Cohort, HCC). This research article uses the direct dynamometry method to provide a detailed analysis of post-COVID survivors’ strength and power characteristics. The Biodex System 4 Pro was utilized to evaluate muscle strength characteristics during the fatigue test. The fatigue work in extensors and flexors was significantly higher in the PCC. The PCC also showed significantly less power in both extensors and flexors compared to the HCC. In conclusion, this study provides compelling evidence of the impact of post-COVID-19 fatigue on muscle performance, highlighting the importance of considering these effects in the rehabilitation and care of individuals recovering from the virus. PCC achieved lower muscle strength values than HCC.

Background: Even though coronary artery disease (CAD) is considered an independent risk factor of an unfavorable outcome of SARS-CoV-2-infection, the clinical course of COVID-19 in subjects with CAD is heterogeneous, ranging from clinically asymptomatic to fatal cases. Since the individual C₂HEST components are similar to the COVID-19 risk factors, we evaluated its predictive value in CAD subjects. Materials and Methods: In total, 2183 patients hospitalized due to confirmed COVID-19 were enrolled onto this study consecutively. Based on past medical history, subjects were assigned to one of two of the study arms (CAD vs. non-CAD) and allocated to different risk strata, based on the C₂HEST score. Results: The CAD cohort included 228 subjects, while the non-CAD cohort consisted of 1956 patients. In-hospital, 3-month and 6-month mortality was highest in the high-risk C₂HEST stratum in the CAD cohort, reaching 43.06%, 56.25% and 65.89%, respectively, whereas in the non-CAD cohort in the high-risk stratum, it reached: 26.92%, 50.77% and 64.55%. Significant differences in mortality between the C₂HEST stratum in the CAD arm were observed in post hoc analysis only for medium- vs. high-risk strata. The C₂HEST score in the CAD cohort could predict hypovolemic shock, pneumonia and acute heart failure during hospitalization, whereas in the non-CAD cohort, it could predict cardiovascular events (myocardial injury, acute heart failure, myocardial infract, carcinogenic shock), pneumonia, acute liver dysfunction and renal injury as well as bleedings. Conclusions: The C₂HEST score is a simple, easy-to-apply tool which might be useful in risk stratification, preferably in non-CAD subjects admitted to hospital due to COVID-19.

Functional Mobility Assessment (FMA) is a challenging task. One example of an FMA is an instrumented Timed Up and Go test (iTUG). Sensor-based interventions are more effective than traditional interventions that use clinical tests to assess a patient’s FMA. Background/Objectives: The aim of this study is to investigate the variability of selected parameters of the instrumented Time Up and Go test using inertial measurements in healthy younger adults. Methods: A total of 73 subjects participated in the study, including 37 women and 36 men. The mean age was 31 years (SD 5.5 years), the mean height [cm] was 176.2 (SD 91), and the mean BMI [kg/m²] was 26.6 (SD 3.1). The Noraxon MyoMotion Research 18 motion analysis system was used to record raw spatial data. Results: The mean total time to complete the iTUG test was 13.1 ± 1.9 s with a low coefficient of variation (CV), suggesting consistent performance between participants. The recorded spatial and temporal parameters of the gait variables, as well as the kinematic variables of the iTUG test of the studied group of healthy adults, show low variability, except for the mean double support ratio (R − L)/(R + L), which was 4.1 ± 11.0% with a CV of 271.5%, indicating a very high variability. Conclusions: The low variability observed in key parameters, such as total time and percentage of posture, suggests that the iTUG test provides reliable, objective, and reproducible measurements that can serve as normative benchmarks for healthy adults.