Low Risk of SARS-CoV-2 Reinfection for Fully or Boosted mRNA Vaccinated Subjects in Sicily: A Population-Based Study Using Real-World Data.

Background: Reinfections occur as a response to natural infections wanes and novel strains of SARS-CoV-2 emerge. The present research explored the correlation between sex, age, COVID-19 vaccination, prior infection hospitalization, and SARS-CoV-2 reinfection in Sicily, Italy. Materials and Methods: A population-based retrospective cohort study was articulated using the vaccination flux from a regional registry and the Sicilian COVID-19 monitoring system of the Italian Institute of Health. Only adult Sicilians were included in the study, and hazard ratios were calculated using Cox regression. Results: Partial vaccination provided some protection (adj-HR: 0.92), when compared to unvaccinated individuals; furthermore, reinfection risk was reduced by full vaccination (adj-HR: 0.43), and the booster dose (adj-HR: 0.41). Males had a lower risk than females of reinfection with SARS-CoV-2 (adj-HR: 0.75). Reinfection with SARS-CoV-2 was diminished by hospitalization during the first infection (adj-HR: 0.78). Reinfection risk was higher among those aged 30-39 and 40-49 compared to those aged 18-29, whereas those aged 60-69, 70-79, and 80+ were statistically protected. Reinfection was significantly more frequent during the wild-type-Alpha, Delta, Delta-Omicron, and Omicron dominance/codominance waves compared to the wild type. Conclusions: This study establishes a solid base for comprehending the reinfection phenomenon in Sicily by pinpointing the most urgent policy hurdles and identifying some of the major factors. COVID-19 vaccination, one of the most effective public health tools, protects against reinfection, mostly caused by the Omicron strain. Elderly and hospitalized people's lower risk suggests stricter PPE use.

Clinical Severity in Different Waves of SARS-CoV-2 Infection in Sicily: A Model of Smith's "Law of Declining Virulence" from Real-World Data.

BACKGROUND: The COVID-19 epidemic had a rapid spread worldwide with a continuous and fast mutation of the virus, resulting in the emergence of several variants of concern (VOC). The aim of this study was to evaluate the severity of each VOC among SARS-CoV-2 infected subjects by investigating deaths, ICU admissions, intubations, and severe critical symptoms. METHODS: An ecological observational study was performed to evaluate mortality rates and clinical characteristics of 321,490 unvaccinated Sicilian SARS-CoV-2 cases observed from 2 March 2020 to 27 March 2022. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by multivariate logistic regression analysis evaluating factors determining a clinical worsening. RESULTS: Delta (adj-OR 3.00, 95% Cls 2.70-3.33) and wild-type (adj-OR 2.41, 95% Cls 2.2-2.62) variants had a higher risk than the Omicron strain for developing critical COVID-19 necessitating intubation and eventually undergoing death. Moreover, males appeared to be significantly more susceptible to developing the worst clinical outcome considered, as did older subjects. CONCLUSIONS: The present study provides evidence of factors implicated in the worsening of SARS-CoV-2-infection-related clinical outcomes. The study highlighted the different roles of VOC, in particular Delta and wild-type, and being male and elderly in the development of a worse clinical outcome.

Assessment of cerebral microbleeds by susceptibility-weighted imaging in Alzheimer's disease patients: A neuroimaging biomarker of the disease.

Purpose The objective of this study was to correlate the presence and distribution of cerebral microbleeds in Alzheimer's disease patients with cerebrospinal fluid biomarkers (amyloid-beta and phosphorylated tau 181 protein levels) and cognitive decline by using susceptibility-weighted imaging magnetic resonance sequences at 1.5 T. Material and methods Fifty-four consecutive Alzheimer's disease patients underwent brain magnetic resonance imaging at 1.5 T to assess the presence and distribution of cerebral microbleeds on susceptibility-weighted imaging images. The images were analyzed in consensus by two neuroradiologists, each with at least 10 years' experience. Dementia severity was assessed with the Mini-Mental State Examination score. A multiple regression analysis was performed to assess the associations between the number and location of cerebral microbleed lesions with the age, sex, duration of the disease, cerebrospinal fluid amyloid-beta and phosphorylated tau 181 protein levels, and cognitive functions. Results A total of 296 microbleeds were observed in 54 patients; 38 patients (70.4%) had lobar distribution, 13 patients (24.1%) had non-lobar distribution, and the remaining three patients (5.6%) had mixed distribution, demonstrating that Alzheimer's disease patients present mainly a lobar distribution of cerebral microbleeds. The age and the duration of the disease were correlated with the number of lobar cerebral microbleeds ( P < 0.001). Cerebrospinal fluid amyloid-beta, phosphorylated tau 181 protein levels, and cognitive decline were correlated with the number of lobar cerebral microbleeds in Alzheimer's disease patients ( P < 0.001). Conclusion Lobar distribution of cerebral microbleeds is associated with Alzheimer's disease and the number of lobar cerebral microbleeds directly correlates with cerebrospinal fluid amyloid-beta and phosphorylated tau 181 protein levels and with the cognitive decline of Alzheimer's disease patients.

Usefulness of quantitative peritumoural perfusion and proton spectroscopic magnetic resonance imaging evaluation in differentiating brain gliomas from solitary brain metastases.

OBJECTIVES: The purpose of our study was to evaluate whether peritumoural perfusion weighted and proton spectroscopic magnetic resonance imaging can be used in differentiating between primary gliomas and solitary metastases. METHODS: Ten low-grade gliomas, eight high-grade gliomas and 10 metastases were prospectively evaluated with magnetic resonance imaging, dynamic susceptibility contrast enhanced perfusion imaging and single-voxel proton magnetic resonance spectroscopy before surgical resection or stereotactic biopsy. Maximal relative cerebral blood volume values were calculated drawing three regions of interest of 2 cm(2) in the non-enhancing peritumoural areas. Maximal relative cerebral blood volume values were normalised to that of contralateral normal-appearing white matter. Maximal choline/creatine ratios were calculated from three voxels of 10 cm(3) placed in the peritumoural areas defined as non-enhancing peritumoural white matter surrounding the tumour. The tumour grade presumed with these values was compared to histopathological grading. Differences in the study parameters between groups were assessed using the Mann-Whitney test. A receiver operating characteristic analysis was performed to determine cut-off values. RESULTS: A clear relative cerebral blood volume cut-off value of 1.88 was detected for differentiating low-grade gliomas from high-grade gliomas. A clear relative cerebral blood volume cut-off value of 1.20 was detected for differentiation of metastases from gliomas. The differences in the choline/creatine ratios in the peritumoural regions of high-grade gliomas and of solitary metastasis were statistically significant (P < 0.001) but a clear cut-off value was not found. CONCLUSION: Our preliminary data support the hypothesis that peritumoural perfusion-weighted imaging can assist in preoperative differentiation between a glioma and a solitary metastasis.

Prognostic value of hyperattenuating middle cerebral artery sign at CT in cerebral infarction.

PURPOSE: To assess the prognostic value of hyperattenuating middle cerebral artery sign at CT in acute cerebral infarction. MATERIALS AND METHODS: Ninety-two patients with acute cerebral infarction in the sylvian area were retrospectively reviewed. All patients underwent unenhanced CT 12-24 hours after the onset of symptoms and follow-up CT within 48-72 hours. Initial CT scans were evaluated by consensus by three radiologists to confirm or exclude the presence of hyperattenuating middle cerebral artery sign. History, cardiovascular risk factors and neurological impairment at discharge (mean 25 days) were recorded for each patient. The degree of disability was graded 0 (no disability) to 6 (death). Patients were divided into two groups: patients without (group A) and patients with (group B) hyperattenuating middle cerebral artery sign. A logistic regression analysis was performed to compare the two groups. Results were correlated with cardiovascular risk factors. Kaplan-Meier survival curves were calculated for each group. RESULTS: Hyperattenuating middle cerebral artery sign was present in 18 patients (19.6%) (group B). The percentage of neurological deficits was significantly higher in group B than in group A (p<0.05). Sixteen (88.9%) of the 18 patients in group B had a poor prognostic index (score 3 - 6) with a significantly higher percent difference (41.6%, p<0.05) than patients of group A. Within 10 days of admission, 3 patients (16.7%) died in group A and 6 (8.1%) in group B. However, no significant differences were observed in the Kaplan-Meier survival curves. No correlation with cardiovascular risk factors was observed. CONCLUSIONS: Besides having an important diagnostic value, hyperattenuating middle cerebral artery sign is a reliable predictor of prognosis in terms of disability rather than mortality, as it reflect the larger extension of infarction.