The differential diagnosis of Fever of Unknown Origin (FUO) is very extensive, and includes infectious diseases (ID), neoplasms and noninfectious inflammatory diseases (NIID). Many FUO remain undiagnosed. Factors influencing the final diagnosis of FUO are unclear. To identify factors associated with FUO diagnostic categories, we performed a systematic review of classical FUO case-series published in 2005–2015 and including patients from 2000. Moreover, to explore changing over time, we compared these case-series with those published in 1995–2004. Eighteen case-series, including 3164 patients, were included. ID were diagnosed in 37.8% of patients, NIID in 20.9%, and neoplasm in 11.6%, FUO were undiagnosed in 23.2%. NIIDs significantly increased over time. An association exists between study country income level and ID (increasing when the income decreases) and undiagnosed FUO (increasing when the income increases); even if not significant, the use of a pre-defined Minimal Diagnostic Work-up to qualify a fever as FUO seems to correlate with a lower prevalence of infections and a higher prevalence of undiagnosed FUO. The multivariate regression analysis shows significant association between geographic area, with ID being more frequent in Asia and Europe having the higher prevalence of undiagnosed FUO. Significant associations were found with model of study and FUO defining criteria, also. Despite advances in diagnostics, FUO still remains a challenge, with ID still representing the first cause. The main factors influencing the diagnostic categories are the income and the geographic position of the study country.

COVID-19 is a global threat that has spread since the end of 2019, causing severe clinical sequelae and deaths, in the context of a world pandemic. The infection of the highly pathogenetic and infectious SARS-CoV-2 coronavirus has been proven to exert systemic effects impacting the metabolism. Yet, the metabolic pathways involved in the pathophysiology and progression of COVID-19 are still unclear. Here, we present the results of a mass spectrometry-based targeted metabolomic analysis on a cohort of 52 hospitalized COVID-19 patients, classified according to disease severity as mild, moderate, and severe. Our analysis defines a clear signature of COVID-19 that includes increased serum levels of lactic acid in all the forms of the disease. Pathway analysis revealed dysregulation of energy production and amino acid metabolism. Globally, the variations found in the serum metabolome of COVID-19 patients may reflect a more complex systemic perturbation induced by SARS-CoV-2, possibly affecting carbon and nitrogen liver metabolism.

In Emergency and Medical Admission Departments (EDs and MADs), prompt recognition and appropriate infection control management of patients with Highly Infectious Diseases (HIDs, e.g. Viral Hemorrhagic Fevers and SARS) are fundamental for avoiding nosocomial outbreaks.

Highly Infectious Diseases (HIDs) are (i) easily transmissible form person to person; (ii) cause a life-threatening illness with no or few treatment options; and (iii) pose a threat for both personnel and the public. Hence, even suspected HID cases should be managed in specialised facilities minimizing infection risks but allowing state-of-the-art critical care. Consensus statements on the operational management of isolation facilities have been published recently. The study presented was set up to compare the operational management, resources, and technical equipment among European isolation facilities. Due to differences in geography, population density, and national response plans it was hypothesized that adherence to recommendations will vary. Until mid of 2010 the European Network for Highly Infectious Diseases conducted a cross-sectional analysis of isolation facilities in Europe, recruiting 48 isolation facilities in 16 countries. Three checklists were disseminated, assessing 44 items and 148 specific questions. The median feedback rate for specific questions was 97.9% (n = 47/48) (range: n = 7/48 (14.6%) to n = 48/48 (100%). Although all facilities enrolled were nominated specialised facilities' serving countries or regions, their design, equipment and personnel management varied. Eighteen facilities fulfilled the definition of a High Level Isolation Unit'. In contrast, 24 facilities could not operate independently from their co-located hospital, and five could not ensure access to equipment essential for infection control. Data presented are not representative for the EU in general, as only 16/27 (59.3%) of all Member States agreed to participate. Another limitation of this study is the time elapsed between data collection and publication; e.g. in Germany one additional facility opened in the meantime. There are disparities both within and between European countries regarding the design and equipment of isolation facilities. With regard to the International Health Regulations, terminology, capacities and equipment should be standardised.

We aimed to study whether people living with HIV (PLWH) are at higher risk of in-hospital COVID-19 mortality compared to the general population (GenPop). This was a retrospective study in 19 Italian centers (February 2020 to November 2022) including hospitalized PLWH and GenPop with SARS-CoV-2 infection. The main outcome was in-hospital mortality. Competing risk analyses by Fine-Gray regression model were used to estimate the association between in-hospital mortality and HIV status/age. A total of 7399 patients with COVID-19 were included, 239 (3.2%) PLWH, and 7160 (96.8%) GenPop. By day 40, in-hospital death occurred in 1283/7160 (17.9%) among GenPop and 34/239 (14.2%) among PLWH. After adjusting for potential confounders, compared to GenPop <65 years, a significantly higher risk of death was observed for GenPop ≥65 (adjusted subdistribution hazard ratio [aSHR] 1.79 [95% CI 1.39-2.31]), PLWH ≥65 (aSHR 2.16 [95% CI 1.15-4.04]), PLWH <65 with CD4 ≤200 (aSHR 9.69 [95% CI 5.50-17.07]) and PLWH <65 with CD4 201-350 (aSHR 4.37 [95% CI 1.79-10.63]), whereas no evidence for a difference for PLWH 350 (aSHR 1.11 [95% CI 0.41-2.99]). In PLWH aged <65 years a CD4 ≤350 rather than HIV itself seems the driver for the observed higher risk of in-hospital mortality. We cannot however rule out that HIV infection per se is the risk factor in those aged ≥65 years.