Search Results (1,678)

Background and Objectives: Healthcare-associated infections (HAIs) remain a major cause of morbidity and mortality among hospitalized patients. During the COVID-19 pandemic, SARS-CoV-2 infection emerged as a major contributor to HAIs, alongside Clostridioides difficile infection (CDI) and other bacterial infections. This study aimed to evaluate the clinical characteristics and outcomes of HAIs in surgical departments and to identify factors associated with in-hospital mortality. Materials and Methods: We conducted a retrospective observational study including 170 patients with documented HAIs admitted between July 2018 and June 2022 in surgical departments of a county emergency hospital. Patients were categorized into SARS-CoV-2 infection (n = 85), CDI (n = 73), and other bacterial infections (n = 12), the latter being included for descriptive purposes only due to limited sample size. Clinical variables, comorbidities, prior antibiotic exposure, length of hospital stay, and in-hospital mortality were analyzed. Survival analysis and logistic regression were performed to identify predictors of mortality. Results: SARS-CoV-2 infection represented the largest subgroup, followed by CDI. Overall, in-hospital mortality was 15.9%, with comparable rates between SARS-CoV-2 infection (17.6%) and CDI (16.4%), while no deaths were observed in the small subgroup of other bacterial infections. CDI patients had a significantly higher burden of comorbidities (p = 0.004). Kaplan–Meier analysis did not show a statistically significant difference in survival between SARS-CoV-2 and CDI groups (log-rank p = 0.28). In univariate analysis, acute respiratory failure (OR ≈ 13.5, p < 0.001), chronic kidney disease (OR ≈ 4.4, p = 0.018), and number of comorbidities (p = 0.019) were associated with mortality, but none remained significant in multivariable analysis. Conclusions: In-hospital mortality was similar between SARS-CoV-2 infection and CDI, highlighting the persistent clinical impact of CDI in hospitalized patients. Comorbidity burden and acute complications, particularly respiratory failure, were key determinants of mortality. These findings highlight the persistent clinical impact of CDI and the role of comorbidity burden and acute complications, particularly respiratory failure, in shaping in-hospital mortality. The absence of independent predictors in multivariable analysis should be interpreted cautiously given the limited sample size. Full article

A three-year (January 2020–December 2022) daily dataset of 16 polycyclic aromatic hydrocarbons (PAHs) collected in parallel with PM_2.5 and a suite of meteorological variables at a coastal Mediterranean urban site in southern Italy (Pomigliano d’Arco, Campania) is presented and analysed. Raw PAH time series were decomposed into a long-term trend component (LT), a seasonal component (ST), and a residual component (RT) using an iterative missing-value-robust Kolmogorov–Zurbenko (KZ) moving-average filter. Spearman rank correlations between PAH concentrations and four meteorological predictors (mean temperature, relative humidity, mean wind speed, and maximum wind speed) were computed for each congener. Diagnostic molecular ratios—Fla/(Fla + Pyr), BaP/BghiP, Indeno[1,2,3-cd]pyrene/(IcdP + BghiP), and BaA/(BaA + Chr)—were evaluated seasonally and interpreted jointly with an information-theoretic Bayesian mixture modelling procedure (SNOB/MML) and with the documented susceptibility of some PAH ratios, especially BaP-containing ratios, to atmospheric ageing, phase repartitioning and summer photodegradation. Total PAH concentrations (sum of 16 congeners) ranged from <1 ng m⁻³ in summer to 46 ng m⁻³ during winter high-pollution episodes, with BaP peaking at ≈6.7 ng m⁻³. Because BaP was measured in the PM_2.5 fraction, comparisons with the EU annual target value of 1 ng m⁻³ established for PM₁₀-bound BaP are treated as indicative context only, not as formal compliance statements. Pronounced seasonal variability was driven primarily by residential heating emissions, and the incremental lifetime cancer risk (ILCR) for inhalation exposure reached $1.03\times {10}^{-4}$ (95% CI: $0.88$–$1.20\times {10}^{-4}$) during the heating season under a continuous outdoor-exposure worst-case scenario. The absolute ILCR magnitude is conditional on the selected TEF scheme and on the adopted BaP unit-risk coefficient; under an additional indoor-dominated scenario (16 h day⁻¹, infiltration factor 0.6), the corresponding risk remained above the conventional ${10}^{-6}$ benchmark. An anomalous near-background PAH signal during spring 2020 is attributed to the COVID-19 national lockdown, which reduced total PAH concentrations by approximately 85% relative to the seasonal component predicted by the iterative moving-average filter for the same calendar window. Source apportionment via diagnostic ratios identifies residential/biomass combustion as the dominant cold-season source and vehicular emissions as the prevailing warm-season source. These results provide a novel characterisation of PAH pollution dynamics in the undersampled southern Mediterranean and provide evidence to support targeted abatement policies. Full article

Objectives: Changes in public policy are eroding vaccine confidence. Previously accepted peer-reviewed evidence around vaccination and developmental outcomes for children is being questioned. Robust, methodologically sound safety data are more needed than ever to maintain consumer confidence. Establishing further safety data on infant health, development, and allergies after COVID-19 and influenza vaccination in pregnancy may improve confidence and acceptance. Methods: This is a state-wide multi-centre prospective cohort study conducted as a sub-study of the Generation Victoria birth cohort. It will examine the risk difference for infant health, developmental, and allergy outcomes between groups of mother–baby pairs who will be examined according to exposure (vaccination against a respiratory virus during pregnancy) and comparator (no vaccination against a respiratory virus). Results: Data contributing to the analysis include GenV-collected developmental, health, and allergy outcomes to 12 months of age, as well as data from state-wide linked datasets. Conclusions: This linked-data longitudinal study will provide information on health, allergy, and developmental outcomes for infants in the first year of life after influenza and COVID-19 vaccination during pregnancy. Implications for Public Health: The reporting of developmental data will be a new contribution to knowledge around outcomes after vaccination during pregnancy. Full article

Background and Objectives: Pediatric forearm fractures are among the most common childhood injuries. COVID-19-related societal restrictions, including school closures and suspension of sports activities, altered children’s daily routines and may have influenced injury patterns. This study aimed to evaluate whether periods of stricter COVID-19 restrictions were associated with changes in the incidence of pediatric distal and diaphyseal forearm fractures after accounting for seasonal variation and long-term temporal trends. Materials and Methods: This retrospective observational time-series study analyzed pediatric patients aged 0–17 years who underwent forearm radiography between January 2018 and June 2023 at a tertiary pediatric trauma center. Cases with radiologically confirmed distal or diaphyseal forearm fractures or epiphyseal injuries were included. Monthly fracture counts were analyzed using generalized linear models with logarithmic link functions. Exposure variables included a COVID-19 restriction index based on governmental measures and a binary pandemic indicator. Seasonal variation and long-term temporal trends were included as covariates. Results: A total of 5702 forearm radiographs were identified, of which 4041 trauma-related presentations met the inclusion criteria. Among these, 2014 children had confirmed forearm fractures. Boys accounted for 61% of cases, and the median age was 9 years (IQR 5). Most fractures were treated conservatively (88%). The most frequent injury mechanisms included soccer-related injuries (9.6%) and bicycle falls (7.3%). In regression analyses adjusted for seasonal variation and temporal trends, neither the COVID-19 restriction index (IRR 1.01, 95% CI 0.87–1.17; p = 0.95) nor the pandemic period indicator (IRR 0.99, 95% CI 0.37–2.65; p = 0.98) was significantly associated with monthly fracture counts. The wide confidence interval of the pandemic indicator reflects limited statistical precision and suggests that both clinically relevant decreases and increases in fracture incidence cannot be excluded. Conclusions: No sustained long-term changes in the incidence or injury patterns of pediatric forearm fractures were observed during the COVID-19 pandemic. Temporary fluctuations during early lockdown phases were not independently associated with governmental restrictions after adjustment for seasonal variability and long-term trends. Full article

Vitamin D has been implicated in immune modulation and susceptibility to respiratory infections, including COVID-19. However, data in asymptomatic pediatric populations, particularly those with household exposure, remain limited. This study aimed to investigate the association between serum vitamin D levels and hematological parameters with SARS-CoV-2 PCR positivity in asymptomatic children, and to evaluate their potential role in early risk stratification. This retrospective study included 127 asymptomatic children (aged 2–18 years) with confirmed household exposure to COVID-19. Participants were classified as PCR-positive (n = 74) or PCR-negative (n = 53). Serum 25(OH)D3 levels and hematological parameters were analyzed. Univariate and multivariable logistic regression analyses were performed to identify independent predictors. Receiver operating characteristic (ROC) curve analysis was used to assess discriminative performance, and a combined multimarker model was constructed. Serum vitamin D levels were significantly lower in PCR-positive children compared to PCR-negative children (17 ± 8 vs. 27 ± 11 ng/mL, p = 0.001). White blood cell (p = 0.002), platelet (p = 0.01), and neutrophil counts (p = 0.01) were significantly reduced, while basophil counts were higher in PCR-positive children (p = 0.02). In multivariable analysis, vitamin D (OR: 0.87, 95% CI: 0.82–0.93, p < 0.001), platelet (p = 0.02), neutrophil (p = 0.02), and basophil counts (p = 0.01) remained independent predictors. ROC analysis showed that vitamin D had moderate discriminative performance (AUC: 0.75, 95% CI: 0.67–0.83), while platelet (AUC: 0.64), neutrophil (AUC: 0.61), and basophil (AUC: 0.62) counts showed modest performance. The combined multimarker model demonstrated improved predictive ability (AUC: 0.80, 95% CI: 0.72–0.88), with sensitivity of 71.6% and specificity of 68.2%. Additionally, vitamin D deficiency was significantly more frequent in PCR-positive children (43% vs. 19%, p = 0.003). Conclusions: Lower vitamin D levels and associated hematological alterations are independently associated with SARS-CoV-2 PCR positivity in asymptomatic children. A combined biomarker approach may improve early risk stratification using simple and routinely available parameters. Further prospective studies are needed to validate these findings and clarify the role of vitamin D in preventive strategies. Full article

Hemoglobin A1c is a central biomarker for long-term glycemic control and a key predictor of diabetes-related complications. The COVID-19 pandemic disrupted routine healthcare delivery and introduced potential metabolic effects of SARS-CoV-2 infection, yet the long-term impact of COVID-19 on glycemic trajectories in individuals with diabetes remains unclear. In this retrospective study, we leveraged harmonized electronic health record data from the National Clinical Cohort Collaborative to evaluate changes in HbA1c before and after documented SARS-CoV-2 infection in adults with diabetes (n = 93,320). Patients were required to have repeated HbA1c measurements pre- and post-infection and stable exposure to key antihyperglycemic medications. A paired statistical analysis was used to identify individuals with statistically significant post-infection changes in HbA1c. We then developed and evaluated multiple supervised machine learning classifiers using an 80/20 train–test split and cross-validation to assess demographic, clinical, and structural factors associated with significant glycemic change. Most patients (71%) did not experience a statistically significant change in average HbA1c following COVID-19 infection, and among those who did, decreases were more common than increases. A random forest classifier achieved the best overall performance, and feature importance and SHAP analyses highlighted body mass index, insulin use, age, and socioeconomic proxies as key contributors. These findings suggest that while COVID-19 infection does not substantially alter long-term glycemic control for most patients with diabetes, individual-level clinical and structural factors influence post-infection glycemic variability. Full article

Supplemental oxygen is a cornerstone intervention in modern clinical practice, widely used to correct hypoxemia in emergency, perioperative, and critical care settings. While oxygen therapy is lifesaving, accumulating evidence indicates that excessive oxygen exposure can induce significant pathophysiological disturbances, particularly within the cardiovascular and pulmonary systems. Hyperoxia (PaO₂ > 100 mm Hg) promotes the generation of reactive oxygen species (ROS), leading to oxidative stress, mitochondrial dysfunction, and the activation of pro-fibrotic pathways. When combined with mechanical ventilation, these effects are further amplified through alterations in intrathoracic pressure, reduced venous return, and increased pulmonary vascular resistance, collectively imposing hemodynamic stress on the myocardium. These mechanical and biochemical perturbations converge to drive structural, functional, and electrical remodeling of the heart, including conduction abnormalities and arrhythmogenesis. Emerging clinical insights, particularly from critically ill and COVID-19 populations, underscore the importance of titrated oxygen strategies that balance adequate tissue oxygenation with minimization of hyperoxic injury. This review synthesizes current evidence on hyperoxia-induced oxidative stress, heart-lung interactions, and mechanisms underlying myocardial remodeling to provide a comprehensive framework for optimizing oxygen therapy. Full article

Background and Objectives: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy has raised concerns regarding possible fetal consequences, including potential effects on auditory system development. Although the current literature suggests that overt congenital hearing loss is uncommon among newborns exposed in utero, subtle cochlear functional alterations may not be detectable through conventional threshold-based screening alone. The objective of this study is to investigate whether in utero exposure to maternal COVID-19 is associated with early cochlear functional changes in newborns, as assessed by frequency-specific transient evoked otoacoustic emission (TEOAE) amplitude ratios, and to determine whether such alterations are accompanied by differences in click-evoked auditory brainstem response (ABR) thresholds. Materials and Methods: This prospective cohort study was conducted between October 2021 and September 2022 and included 61 pregnant women: 30 with laboratory-confirmed SARS-CoV-2 infection during pregnancy (study group) and 31 without documented infection (control group). All newborns underwent standardized audiological evaluation shortly after birth, including otoscopy, TEOAE, click-evoked ABR, and tympanometry. Frequency-specific TEOAE amplitude ratios at 500, 1000, 1500, 2000, and 4000 Hz were compared between groups. A logistic regression analysis was performed to identify audiological predictors of newborn exposure to SARS-CoV-2 in utero. Results: No significant differences were observed in ABR thresholds or in TEOAE “pass/refer” outcomes between the control and study groups, indicating the absence of clinically overt HL. However, newborns exposed to SARS-CoV-2 in utero showed significantly reduced TEOAE amplitude ratios at 2000 Hz (p = 0.0077) and 4000 Hz (p = 0.020). Logistic regression identified the 4000 Hz amplitude ratio as an independent negative predictor of in utero exposure (OR = 0.75; p = 0.0352). No significant differences were detected at lower frequencies. Conclusions: Maternal COVID-19 during pregnancy was not associated with immediate neonatal HL but was linked to subtle high-frequency cochlear functional modulation. Longitudinal audiological follow-up is needed to clarify the clinical significance of these findings. Full article

Background: Hospital-acquired multidrug-resistant organism (HA-MDRO) infections remain a major patient-safety threat linked to antimicrobial exposure, but long-term hospital-level evidence on whether integrated stewardship can reduce HA-MDRO burden remains limited. Methods: We conducted a quasi-experimental interrupted time-series study at a large multi-campus tertiary teaching hospital in China. A hospital-wide integrated intervention combining diagnostic stewardship and antimicrobial prescribing stewardship was implemented on 1 November 2021. Monthly aggregated hospital data from July 2018 to December 2024, including 2,145,489 hospitalizations, were analyzed. The primary outcome was HA-MDRO infection incidence density per 1000 patient-days. Results: HA-MDRO incidence density decreased immediately at the start of the COVID period (IRR = 0.246; p < 0.001) and then increased over time (IRR per month = 1.074; p < 0.001). After intervention implementation, the post-intervention trend declined significantly relative to the COVID-period trajectory (IRR per month = 0.938; p < 0.001). Microbiological testing increased immediately and continued to rise (OR = 1.381 and 1.016 per month, respectively), whereas restricted antibiotic use declined after implementation (OR = 0.979 per month; all p < 0.05). The control outcome showed no consistent post-intervention change. Counterfactual analysis estimated that 15,274 HA-MDRO cases were averted over follow-up. Conclusions: A hospital-wide integrated stewardship intervention was associated with reversal of the increasing HA-MDRO trajectory observed during the COVID period, together with improved microbiological testing and reduced restricted antibiotic use. These findings support the value of integrating diagnostic and prescribing stewardship in high-volume tertiary hospital settings. Full article

Cationic surfactants from quaternary ammonium compounds (QACs) are increasingly recognized as relevant micropollutants particularly following their widespread use during and after the COVID-19 pandemic. The new EU Urban Wastewater Treatment Directive (2024/3019) highlights micropollutant removal as a regulatory priority, mandating advanced treatment for their elimination. In this context, this study examined benzalkonium chloride (BAC) retention and membrane response during nanofiltration (NF) and reverse osmosis (RO), across concentrations ranging from monomeric to micellar. RO membranes achieved >97% rejection, whereas NF showed 65–96% removal strongly affected by micelle formation. Flux decline was most pronounced in RO, with relative permeability (J/J₀) decreasing to ~0.12 at 1.0 CMC, while NF membranes exhibited better hydraulic stability. Membrane active layer zeta potential measurements confirmed adsorption and charge neutralization, with shifts toward less negative values after BAC exposure. Hermia model analysis revealed that fouling was governed by cake layer formation or pore blocking, depending on membrane type and feed concentration. Full article

Understanding how clinical symptoms relate to immune responses during major variant transitions remains important for informing post-pandemic surveillance and vaccination strategies. This study compared symptom patterns and SARS-CoV-2-specific anti-RBD IgM and anti-S1 IgG antibody responses among vaccinated individuals infected during the pre-Omicron and Omicron-dominant periods, representing a key phase in the evolution of SARS-CoV-2 population immunity. A retrospective analysis of 216 confirmed COVID-19 cases was performed by evaluating 11 predefined symptoms together with anti-RBD IgM and anti-S1 IgG levels measured at Day-14 after symptom onset, corresponding to the period when humoral antibody responses are detectable following SARS-CoV-2 infection. Participants with breakthrough infection during the Omicron-dominant period reported fewer symptoms overall compared to the pre-Omicron period, with a median of three versus four symptoms, respectively. Cough was the most common symptom during the Omicron period (82.1%), followed by sore throat (81.4%) and fever (78.6%). In contrast, loss of taste or smell was significantly more frequent in the pre-Omicron period (64.8% versus 22.9%, p < 0.05). IgG levels were significantly higher during the Omicron period than during the pre-Omicron period, increasing by 42.3%, reflecting enhanced antibody responses likely driven by repeated exposure. A consistent association between cough and elevated IgG levels was observed in both periods (p < 0.05), suggesting an association between symptom presentation and the magnitude of the early humoral response. These findings suggest that while clinical symptom profiles evolved across a major SARS-CoV-2 variant transition, certain symptom–antibody relationships remained consistent. Such associations may provide insight into how clinical manifestations relate to immune responses in populations with pre-existing immunity and may support interpretation of symptomatic infection during ongoing SARS-CoV-2 circulation. Full article

Coronavirus Disease 2019 (COVID-19) and other lower respiratory tract diseases (LRTDs), including bacterial pneumonia and acute respiratory distress syndrome, share overlapping clinical features but arise from distinct pathophysiological mechanisms. The molecular signatures that distinguish these diseases remain insufficiently characterized in African populations, where genetic background, endemic infections, and environmental exposures may substantially shape immune responses. We integrated spatially resolved single-cell transcriptomic profiles from lung autopsy specimens of 30 Malawian patients, including 10 with COVID-19, 12 with other LRTDs, and 8 non-LRTD controls. In total, 61,391 cells representing 15 cell types and 36,602 gene expression features were analyzed. Using an integrated machine learning framework that combined nine feature-ranking algorithms with incremental feature selection, we identified potential molecular signatures that could discriminate among disease states within this cohort. The optimal classification models achieved weighted F1 scores greater than 0.94, demonstrating a robust capacity to differentiate COVID-19 from other LRTDs in our dataset. Notably, the macrophage-associated state in COVID-19 was dominated by an IFN-γ response with upregulation of CD163 and HLA-DQA2, contrasting sharply with the type I/III interferon signature reported in European cohorts. In addition, we observed cell-type-specific COVID-19 signatures, including downregulation of CAV1 in AT1 cells, consistent with epithelial damage; dysregulation of SFTPC in AT2 cells, suggesting surfactant dysfunction; and upregulation of NFKBIA in neutrophils, indicating altered inflammatory regulation. Gene Ontology enrichment further revealed universal disruption of protein synthesis machinery, along with cell-type-specific alterations in immune activation, epithelial repair, and inflammatory signaling pathways. Full article

The COVID-19 pandemic highlighted the need for effective disinfection strategies in order to minimize human exposure and reduce the risk of contagion in indoor environments. Ultraviolet-C (UV-C) irradiation has proven to be an effective solution for inactivating a wide range of pathogens. However, traditional fixed UV-C systems suffer from limited coverage and lack operational flexibility. To address these limitations, this paper proposes an augmented reality (AR)-based teleoperation framework for an omnidirectional mobile robot equipped with a UV-C disinfection light. Unlike traditional toolchain integrations, our framework synergizes immersive spatial visualization of a reconstructed environment, operator-guided waypoint-based remote navigation, and real-time interaction with the disinfection payload in a single operational workflow. The system is implemented using a ROSMASTER X3 Plus robotic platform, which generates a three-dimensional representation of the environment through visual simultaneous localization and mapping using RTAB-Map. The result is a 3D map that is imported into the Unity game engine and deployed to a Meta Quest 3 head-mounted display, enabling immersive visualization and interaction. Communication between the AR interface and the robotic system is achieved via the ROS-TCP-Connection, allowing real-time data exchange and remote robot control. Through the AR interface, the operator can navigate the robot within the scanned environment and activate the UV-C light. Experimental validation conducted in a classroom demonstrates the feasibility of the proposed approach and shows measurable reductions in surface microbial load. These results indicate that our system-level integration of AR-assisted teleoperation with mobile UV-C robotics represents a feasible proof-of-concept for flexible, operator-guided disinfection of indoor spaces. Full article

Background/Objectives: Many frontline healthcare professionals had not previously faced a crisis of the magnitude of the COVID-19 pandemic, and prolonged exposure to high-stress clinical environments may adversely affect psychological well-being. This study aimed to assess and compare burnout severity among critical care nurses in two clinical settings—one hospital in Croatia and one in Poland—with particular attention to emotional exhaustion, depersonalization, and personal accomplishment in the post-pandemic period. Methods: A cross-sectional comparative design was conducted across two hospitals (Croatia and Poland). Data were collected from 346 critical care nurses between September and December 2023. Burnout was assessed using the Maslach Burnout Inventory Human Services Survey, analyzed primarily as continuous scores across its three dimensions. Results: No statistically significant differences were observed between the two groups in continuous burnout scores (Emotional Exhaustion p = 0.224, Depersonalization p = 0.852, Personal Accomplishment p = 0.636, total MBI score p = 0.394). Secondary cut-off-based analyses yielded some categorical differences, including a higher proportion classified as having high burnout in the Polish sample (43.2%) than in the Croatian sample (31.5%); however, these findings were exploratory and should not be interpreted as overriding the primary continuous-score results. Regression analyses demonstrated low explanatory power, with education level emerging as a significant predictor only in the Croatian sample (OR = 0.320, 95% CI: 0.125–0.824, p = 0.018). Conclusions: Burnout severity did not differ significantly between the two clinical settings when assessed using continuous measures. These findings suggest that burnout among ICU nurses may be driven primarily by shared occupational and organizational stressors rather than setting-specific differences. Categorical findings should be interpreted as complementary and exploratory. Full article

Background/Objective: This study is a cross-sectional investigation of long-term immune responses measured at different time intervals after COVID-19 infections, vaccinations, or combined exposure. The focus is on immune reactivity against recombinant spike (S) and nucleocapsid (N) protein antigens. Materials and Methods: Serum antibody levels were assessed up to four to four and a half years after infection or immunization, including virus-specific immunoglobulin G (IgG), IgA and IgM antibodies, as well as neutralizing antibodies against the S-protein. Cellular immunity was assessed by analyzing peripheral blood mononuclear cells (PBMC; n = 43 in first cohort, n = 32 in second cohort), including T-helper memory and cytotoxic subsets, and cytokine production after in vitro stimulation with recombinant SARS-CoV-2 proteins. A multiplex cytokine assay was used to analyze effector and regulatory immune responses. Results: Virus-specific IgG antibodies persisted for years after exposure to SARS-CoV-2, with IgG against the receptor-binding domain (RBD) correlating most strongly with neutralizing activity. Vaccinated individuals demonstrated higher IgA responses, whereas antibodies to the N-protein were associated with previous infection. No IgM antibodies were detected in any subjects, suggesting an immune response based on memory rather than ongoing infection. PBMCs from individuals with a history of both COVID-19 exposure and vaccination exhibited enhanced responsiveness, characterized by increased frequencies of memory T cells compared to vaccination alone. Stimulating with the S-protein induces higher cytokine production, including IFN-gamma, TNF-alfa, and IL-12(p70), compared with stimulation by the N-protein. Cytokines such as IL-10 and TGF-beta are also elevated, suggesting immune regulation rather than persistent inflammation. Conclusions: SARS-CoV-2 infection and vaccination are associated with persistent humoral and cellular immune responses detectable several years after exposure. Individuals with hybrid immunity exhibit broader and functionally enhanced immune reactivity, indicating more robust long-term immune memory. Future studies should focus on the long-term consequences of hybrid immunity and optimize other vaccine strategies, including recombinant antigen vaccines. Full article