Intensive Care Unit Mortality Trends during the First Two Years of the COVID-19 Pandemic in Greece: A Multi-Center Retrospective Study.

Data on COVID-19 mortality among patients in intensive care units (ICUs) from Eastern and/or Southern European countries, including Greece, are limited. The purpose of this study was to evaluate the ICU mortality trends among critically ill COVID-19 patients during the first two years of the pandemic in Greece and to further investigate if certain patients' clinical characteristics contributed to this outcome. We conducted a multi-center retrospective observational study among five large university hospitals in Greece, between February 2020 and January 2022. All adult critically ill patients with confirmed COVID-19 disease who required ICU admission for at least 24 h were eligible. In total, 1462 patients (66.35% males) were included in this study. The mean age of this cohort was 64.9 (±13.27) years old. The 28-day mortality rate was 35.99% (n = 528), while the overall in-hospital mortality was 50.96% (n = 745). Cox regression analysis demonstrated that older age (≥65 years old), a body mass index within the normal range, and a delay in ICU admission from symptom onset, as well as worse baseline clinical severity scores upon ICU admission, were associated with a greater risk of death. Mortality of critically ill COVID-19 patients was high during the first two years of the pandemic in Greece but comparable to other countries. Risk factors for death presented in this study are not different from those that have already been described for COVID-19 in other studies.

SARS-CoV-2 seroprevalence among children in Greece during Omicron variant period.

The Omicron variant is associated with increased transmissibility, but evidence about the impact of Omicron in seropositivity of children is limited. This study aims to evaluate SARS-CoV-2 seroprevalence in children during the different variants' subperiods. A prospective multicenter seroprevalence study was conducted in 7 University public hospitals in Greece from November 2021 to August 2022 (3 subperiods: November 2021-February 2022, March 2022-May 2022, June 2022-August 2022). Children from different age groups, admitted to the hospital or examined in outpatient clinics for reasons other than COVID-19 were enrolled. Neutralizing antibodies (Nabs), anti-Spike (anti-S) and anti-nucleocapsid (anti-N) SARS-CoV-2 IgG in serum were evaluated. A total of 2127 children (males:57,2%; median age:4,8years) were enrolled. Anti-N IgG seropositivity increased from 17,8% in the first sub-period to 40,7% in the second sub-period and then decreased in the third sub-period (36,7%). Anti-S IgG seropositivity appeared to have an increasing trend over the study period, starting from 34,8% and reaching 80,7%. Children aged 1-4 years old have significantly higher anti-N IgG titers compared to children aged 0-1 years old (p < 0,001). Infants have significantly lower anti-S IgG titers compared to all other age groups (p < 0,001). Immunocompromised children and infants have the lowest seropositivity for NAbs.Conclusions During the Omicron period, seropositivity significantly increased, as a result of higher transmissibility. Neonates and infants have lower antibody titers compared to other age groups, while young children aged 1-4 years old present higher antibody titers, suggesting that this age group may mount a higher antibody response. Continuous surveillance seroprevalence studies are needed in children, in order to identify the true extent of SARS-CoV-2 and guide the planning of adequate public health measures.

WHAT IS KNOWN: • Seroprevalence surveys among children may be extremely useful, in order to properly monitor the immunity, either natural or acquired, through the quantification of IgG antibodies and to plan further immunization policies. • There are variations in the seroprevalence of COVID-19 between the different periods, according to the vaccination rates, the type of circulating variant and the transmissibility of the virus. • The Omicron variant is associated with increased transmissibility, but evidence about the impact of Omicron in seropositivity of children is limited. WHAT IS NEW: • In this large multicenter seroepidemiological study, SARS-CoV-2 seroprevalence rate in children is higher during the Omicron period in comparison to the previous pandemic waves, due to the high transmissibility of the virus and the increased rates of reinfection. • Neonates and infants have lower antibody titers compared to other age groups, while young children aged 1­4 years old present higher antibody titers, indicating that the children of this age group mount a higher antibody response. • This study provides essential information about immunity and the level of protection in the pediatric population, as neutralizing antibodies were evaluated, in addition to the anti-N and anti-S IgG antibodies.

The Role of Automated Infrared Pupillometry in Traumatic Brain Injury: A Narrative Review.

Pupillometry, an integral component of neurological examination, serves to evaluate both pupil size and reactivity. The conventional manual assessment exhibits inherent limitations, thereby necessitating the development of portable automated infrared pupillometers (PAIPs). Leveraging infrared technology, these devices provide an objective assessment, proving valuable in the context of brain injury for the detection of neuro-worsening and the facilitation of patient monitoring. In cases of mild brain trauma particularly, traditional methods face constraints. Conversely, in severe brain trauma scenarios, PAIPs contribute to neuro-prognostication and non-invasive neuromonitoring. Parameters derived from PAIPs exhibit correlations with changes in intracranial pressure. It is important to acknowledge, however, that PAIPs cannot replace invasive intracranial pressure monitoring while their widespread adoption awaits robust support from clinical studies. Ongoing research endeavors delve into the role of PAIPs in managing critical neuro-worsening in brain trauma patients, underscoring the non-invasive monitoring advantages while emphasizing the imperative for further clinical validation. Future advancements in this domain encompass sophisticated pupillary assessment tools and the integration of smartphone applications, emblematic of a continually evolving landscape.

Epidemiology of respiratory viruses among children during the SARS-CoV-2 pandemic: A systematic review and meta-analysis.

OBJECTIVE: This meta-analysis aimed to assess the prevalence of respiratory viruses among children under the special conditions of the COVID-19 pandemic. METHODS: Five databases were systematically searched to assess the pooled prevalence of various respiratory viruses in different age groups, regions, seasons, and in patients with and without confirmed SARS-CoV-2 coinfection. Moreover, we looked at the virus distribution in the first and second half of the pandemic and countries with distinct economic status. Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed, and the systematic review was registered on PROSPERO (CRD42022379297). RESULTS: Enterovirus/rhinovirus and human respiratory syncytial virus (HRSV) were the most prevalent pathogens among children. The prevalence of HRSV increased in the second half of the pandemic. The prevailing viruses vary according to the SARS-CoV-2-coinfection status, season, region, and country´s economic status. CONCLUSION: This meta-analysis shows the epidemiology of respiratory viruses other than SARS-CoV-2 in children aged 0 to 12 years during the COVID-19 pandemic. Because major events, such as a pandemic, can alter epidemiology patterns, it is important to know them to improve health education measures, develop vaccines and medicines for vulnerable groups, as a guide for prevention strategies, and help with clinical decisions.

Global prevalence of respiratory virus infections in adults and adolescents during the COVID-19 pandemic: A systematic review and meta-analysis.

OBJECTIVES: Since the beginning of the COVID-19 pandemic, efforts have been made to contain the spread of the virus. However, the epidemiological burden of other respiratory viruses during the pandemic is unclear. We aim to address the epidemiology of respiratory viruses on adults/adolescents since the beginning of the pandemic. METHODS: We systematically searched five databases and performed a meta-analysis to explore the pooled prevalence of respiratory viruses in different geographical regions, age groups, and periods and compared the prevalence between COVID-19 cases and non-COVID-19 patients. RESULTS: Enteroviruses/rhinoviruses were highly prevalent compared to other viruses. Different viruses were dominant in different regions. No significant differences in prevalence were found between different age groups, except for human metapneumovirus. There was an increase in prevalence of non-SARS-CoV-2 viruses in the second half of the pandemic (July 2021-December 2022). Comparison of COVID-19 and non-COVID patients showed a higher prevalence in the non-COVID group, significant for influenza, seasonal coronaviruses, and human parainfluenza viruses. CONCLUSION: Our findings indicate that enteroviruses/rhinoviruses were less impacted by healthcare measures compared with other respiratory viruses. The relaxation of measures in the second half led to an increased pooled prevalence of infections. Several factors may explain the lower prevalence among individuals infected with COVID-19.

Endothelial Glycocalyx Integrity in Treatment-Naïve People Living with HIV before and One Year after Antiretroviral Treatment Initiation.

Endothelial glycocalyx (EG) derangement has been associated with cardiovascular disease (CVD). Studies on EG integrity among people living with HIV (PLWH), are lacking. We conducted a prospective cohort study among treatment-naïve PLWH who received emtricitabine/tenofovir alafenamide, combined with either an integrase strand transfer inhibitor (INSTI, dolutegravir, raltegravir or elvitegravir/cobicistat), or a protease inhibitor (PI, darunavir/cobicistat). We assessed EG at baseline, 24 (±4) and 48 (±4) weeks, by measuring the perfused boundary region (PBR, inversely proportional to EG thickness), in sublingual microvessels. In total, 66 consecutive PLWH (60 (90.9%) males) with a median age (interquartile range, IQR) of 37 (12) years, were enrolled. In total, 40(60.6%) received INSTI-based regimens. The mean (standard deviation) PBR decreased significantly from 2.17 (0.29) µm at baseline to 2.04 (0.26) µm (p = 0.019), and then to 1.93 (0.3) µm (p < 0.0001) at 24 (±4) and 48 (±4) weeks, respectively. PBR did not differ among treatment groups. PLWH on INSTIs had a significant PBR reduction at 48 (±4) weeks. Smokers and PLWH with low levels of viremia experienced the greatest PBR reduction. This study is the first to report the benefit of antiretroviral treatment on EG improvement in treatment-naïve PLWH and depicts a potential bedside biomarker and therapeutic target for CVD in PLWH.

New Insights into the Fluid Management in Patients with Septic Shock.

The importance of fluid resuscitation therapy during the early stages of sepsis management is a well-established principle. Current Surviving Sepsis Campaign (SSC) guidelines recommend the early administration of intravenous crystalloid fluids for sepsis-related hypotension or hyperlactatemia due to tissue hypoperfusion, within the first 3 h of resuscitation and suggest using balanced solutions (BSs) instead of normal saline (NS) for the management of patients with sepsis or septic shock. Studies comparing BS versus NS administration in septic patients have demonstrated that BSs are associated with better outcomes including decreased mortality. After initial resuscitation, fluid administration has to be judicious in order to avoid fluid overload, which has been associated with increased mortality, prolonged mechanical ventilation, and worsening of acute kidney injury. The "one size fits all" approach may be "convenient" but it should be avoided. Personalized fluid management, based on patient-specific hemodynamic indices, provides the foundations for better patient outcomes in the future. Although there is a consensus on the need for adequate fluid therapy in sepsis, the type, the amount of administered fluids, and the ideal fluid resuscitation strategy remain elusive. Well-designed large randomized controlled trials are certainly needed to compare fluid choices specifically in the septic patient, as there is currently limited evidence of low quality. This review aims to summarize the physiologic principles and current scientific evidence regarding fluid management in patients with sepsis, as well as to provide a comprehensive overview of the latest data on the optimal fluid administration strategy in sepsis.

Update of European Society of Clinical Microbiology and Infectious Diseases coronavirus disease 2019 guidelines: diagnostic testing for severe acute respiratory syndrome coronavirus 2.

SCOPE: Since the onset of COVID-19, several assays have been deployed for the diagnosis of SARS-CoV-2. The European Society of Clinical Microbiology and Infectious Diseases (ESCMID) published the first set of guidelines on SARS-CoV-2 in vitro diagnosis in February 2022. Because the COVID-19 landscape is rapidly evolving, the relevant ESCMID guidelines panel releases an update of the previously published recommendations on diagnostic testing for SARS-CoV-2. This update aims to delineate the best diagnostic approach for SARS-CoV-2 in different populations based on current evidence. METHODS: An ESCMID COVID-19 guidelines task force was established by the ESCMID Executive Committee. A small group was established, half appointed by the chair, and the remaining selected with an open call. The panel met virtually once a week. For all decisions, a simple majority vote was used. A list of clinical questions using the population, intervention, comparison, and outcome (PICO) format was developed at the beginning of the process. For each PICO, 2 panel members performed a literature search focusing on systematic reviews with a third panellist involved in case of inconsistent results. The panel reassessed the PICOs previously defined as priority in the first set of guidelines and decided to address 49 PICO questions, because 6 of them were discarded as outdated/non-clinically relevant. The 'Grading of Recommendations Assessment, Development and Evaluation (GRADE)-adoption, adaptation, and de novo development of recommendations (ADOLOPMENT)' evidence-to-decision framework was used to produce the guidelines. QUESTIONS ADDRESSED BY THE GUIDELINES AND RECOMMENDATIONS: After literature search, we updated 16 PICO questions; these PICOs address the use of antigen-based assays among symptomatic and asymptomatic patients with different ages, COVID-19 severity status or risk for severe COVID-19, time since the onset of symptoms/contact with an infectious case, and finally, types of biomaterials used.

Autoantibodies are highly prevalent in non-SARS-CoV-2 respiratory infections and critical illness.

The widespread presence of autoantibodies in acute infection with SARS-CoV-2 is increasingly recognized, but the prevalence of autoantibodies in non-SARS-CoV-2 infections and critical illness has not yet been reported. We profiled IgG autoantibodies in 267 patients from 5 independent cohorts with non-SARS-CoV-2 viral, bacterial, and noninfectious critical illness. Serum samples were screened using Luminex arrays that included 58 cytokines and 55 autoantigens, many of which are associated with connective tissue diseases (CTDs). Samples positive for anti-cytokine antibodies were tested for receptor blocking activity using cell-based functional assays. Anti-cytokine antibodies were identified in > 50% of patients across all 5 acutely ill cohorts. In critically ill patients, anti-cytokine antibodies were far more common in infected versus uninfected patients. In cell-based functional assays, 11 of 39 samples positive for select anti-cytokine antibodies displayed receptor blocking activity against surface receptors for Type I IFN, GM-CSF, and IL-6. Autoantibodies against CTD-associated autoantigens were also commonly observed, including newly detected antibodies that emerged in longitudinal samples. These findings demonstrate that anti-cytokine and autoantibodies are common across different viral and nonviral infections and range in severity of illness.

Cardiovascular disease and risk assessment in people living with HIV: Current practices and novel perspectives.

Human immunodeficiency virus (HIV) infection represents a major cardiovascular risk factor, and the cumulative cardiovascular disease (CVD) burden among aging people living with HIV (PLWH) constitutes a leading cause of morbidity and mortality. To date, CVD risk assessment in PLWH remains challenging. Therefore, it is necessary to evaluate and stratify the cardiovascular risk in PLWH with appropriate screening and risk assessment tools and protocols to correctly identify which patients are at a higher risk for CVD and will benefit most from prevention measures and timely management. This review aims to accumulate the current evidence on the association between HIV infection and CVD, as well as the risk factors contributing to CVD in PLWH. Furthermore, considering the need for cardiovascular risk assessment in daily clinical practice, the purpose of this review is also to report the current practices and novel perspectives in cardiovascular risk assessment of PLWH and provide further insights into the development and implementation of appropriate CVD risk stratification and treatment strategies, particularly in countries with high HIV burden and limited resources.

Respiratory viral co-infections in patients with COVID-19 and associated outcomes: A systematic review and meta-analysis.

The aim of this systematic review and meta-analysis was to critically assess the published literature related to community-acquired viral co-infections and COVID-19 and to evaluate the prevalence, most identified co-pathogens, and relevant risk factors. Furthermore, we aimed to examine the clinical features and outcomes of co-infected compared to mono-infected COVID-19 patients. We systematically searched PubMed, Web of Science, Embase, Scopus, and The Cochrane Library for studies published from 1 November 2019 to 13 August 2021. We included patients of all ages and any COVID-19 severity who were screened for respiratory viral co-infection within 48 h of COVID-19 diagnosis. The main outcome was the proportion of patients with a respiratory viral co-infection. The systematic review was registered to PROSPERO (CRD42021272235). Out of 6053 initially retrieved studies, 59 studies with a total of 16,643 SARS-CoV-2 positive patients were included. The global pooled prevalence was 5.01% (95% CI 3.34%-7.27%; I2  = 95%) based on a random-effects model, with Influenza Viruses (1.54%) and Enteroviruses (1.32%) being the most prevalent pathogens. Subgroup analyses showed that co-infection was significantly higher in paediatric (9.39%) than adult (3.51%) patients (p-value = 0.02). Furthermore, co-infected patients were more likely to be dyspnoeic and the odds of fatality (OR = 1.66) were increased. Although a relatively low proportion of COVID-19 patients have a respiratory viral co-infection, our findings show that multiplex viral panel testing may be advisable in patients with compatible symptoms. Indeed, respiratory virus co-infections may be associated with adverse clinical outcomes and therefore have therapeutic and prognostic implications.

Performance of point-of care molecular and antigen-based tests for SARS-CoV-2: a living systematic review and meta-analysis.

BACKGROUND: Molecular and antigen point-of-care tests (POCTs) have augmented our ability to rapidly identify and manage SARS-CoV-2 infection. However, their clinical performance varies among individual studies. OBJECTIVES: The evaluation of the performance of molecular and antigen-based POCTs in confirmed, suspected, or probable COVID-19 cases compared with that of laboratory-based RT-PCR in real-life settings. DATA SOURCES: MEDLINE/PubMed, Scopus, Embase, Web of Science, Cochrane Library, Cochrane COVID-19 study register, and COVID-19 Living Evidence Database from the University of Bern. STUDY ELIGIBILITY CRITERIA: Peer-reviewed or preprint observational studies or randomized controlled trials that evaluated any type of commercially available antigen and/or molecular POCTs for SARS-CoV-2, including multiplex PCR panels, approved by the United States Food and Drug Administration, with Emergency Use Authorization, and/or marked with Conformitè Europëenne from European Commission/European Union. PARTICIPANTS: Close contacts and/or patients with symptomatic and/or asymptomatic confirmed, suspected, or probable COVID-19 infection of any age. TEST/S: Molecular and/or antigen-based SARS-CoV-2 POCTs. REFERENCE STANDARD: Laboratory-based SARS-CoV-2 RT-PCR. ASSESSMENT OF RISK OF BIAS: Eligible studies were subjected to quality-control and risk-of-bias assessment using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. METHODS OF DATA SYNTHESIS: Summary sensitivities and specificities with their 95% CIs were estimated using a bivariate model. Subgroup analysis was performed when at least three studies informed the outcome. RESULTS: A total of 123 eligible publications (97 and 26 studies assessing antigen-based and molecular POCTs, respectively) were retrieved from 4674 initial records. The pooled sensitivity and specificity for 13 molecular-based POCTs were 92.8% (95% CI, 88.9-95.4%) and 97.6% (95% CI, 96.6-98.3%), respectively. The sensitivity of antigen-based POCTs pooled from 138 individual evaluations was considerably lower than that of molecular POCTs; the pooled sensitivity and specificity rates were 70.6% (95% CI, 67.2-73.8%) and 98.9% (95% CI, 98.5-99.2%), respectively. DISCUSSION: Further studies are needed to evaluate the performance of molecular and antigen-based POCTs in underrepresented patient subgroups and different respiratory samples.

Vitamin D supplementation for the treatment of COVID-19: A systematic review and meta-analysis of randomized controlled trials.

Vitamin D supplementation and its impact on immunoregulation are widely investigated. We aimed to assess the prevention and treatment efficiency of vitamin D supplementation in the context of coronavirus disease 2019 (COVID-19) and any disease-related complications. For this systematic review and meta-analysis, we searched databases (PubMed, Embase, Scopus, Web of Science, The Cochrane Library, medRxiv, Cochrane COVID-19 Study Register, and ClinicalTrial.gov) for studies published between 1 November 2019 and 17 September 2021. We considered randomized trials (RCTs) as potentially eligible when patients were tested for SARS-CoV-2 infection and received vitamin D supplementation versus a placebo or standard-of-care control. A random-effects model was implemented to obtain pooled odds ratios for the effect of vitamin D supplementation on the main outcome of mortality as well as clinical outcomes. We identified a total of 5,733 articles, of which eight RCTs (657 patients) met the eligibility criteria. Although no statistically significant effects were reached, the use of vitamin D supplementation showed a trend for reduced mortality [odds ratio (OR) 0.74, 95% confidence interval (CI) 0.32-1.71, p = 0.48] compared with the control group, with even stronger effects, when vitamin D was administered repeatedly (OR 0.33, 95% CI 0.1-1.14). The mean difference for the length of hospitalization was -0.28 (95% CI -0.60 to 0.04), and the ORs were 0.41 (95% CI 0.15-1.12) and 0.52 (95% CI 0.27-1.02) for ICU admission and mechanical ventilation, respectively. In conclusion, vitamin D supplementation did not improve the clinical outcomes in COVID-19 patients, but trends of beneficial effects were observed. Further investigations are required, especially studies focusing on the daily administration of vitamin D.

Myeloid CD169/Siglec1: An immunoregulatory biomarker in viral disease.

CD169, also known as Siglec1 or Sialoadhesin (Sn), is a surface adhesion molecule on human myeloid cells. Being part of the Siglec family, it acts as a receptor for sialylated molecular structures, which are found among various pathogenic and non-pathogenic ligands. Recent data suggest that CD169 may represent a promising new biomarker in acute respiratory and non-respiratory viral infections, such as SARS-CoV-2, Respiratory syncytial virus (RSV) and Human immunodeficiency virus (HIV). Therein lies a great potential to sufficiently differentiate viral from bacterial infection, which has been an incessant challenge in the clinical management of infectious disease. CD169 equips myeloid cells with functions, reaching far beyond pathogen elimination. In fact, CD169 seems to crosslink innate and adaptive immunity by antigen presentation and consecutive pathogen elimination, embodying a substantial pillar of immunoregulation. Yet, our knowledge about the kinetics, mechanisms of induction, signaling pathways and its precise role in host-pathogen interaction remains largely obscure. In this review, we describe the role of CD169 as a potentially novel diagnostic biomarker for respiratory viral infection by evaluating its strengths and weaknesses and considering host factors that are involved in pathogenesis of virus infection. Finally, this brief review aims to point out shortcomings of available evidence, thus, guiding future work revolving the topic.

Future Perspectives in the Diagnosis and Treatment of Sepsis and Septic Shock.

Sepsis, defined as life-threatening organ dysfunction caused by a dysregulated host response to infection, represents the primary cause of death due to infection [...].

Effects of low molecular weight heparin and fondaparinux on mortality, hemorrhagic and thrombotic complications in COVID-19 patients.

Background: Coronavirus disease 2019 (COVID-19) is associated with increased thrombosis prevalence. However, there are insufficient data supporting the appropriate anticoagulation dose in COVID-19. Objective: We aim to systematically assess the currently available data regarding the effects of different dosing regimens of low molecular weight heparin and/or fondaparinux (LMWH/F) on mortality risk as well as the risk of arterial/venous thrombotic events and hemorrhagic complications in confirmed COVID-19 cases. Design: We conducted a living systematic review and meta-analysis on the effects of different LMWH/F doses on mortality, thrombotic and hemorrhagic events in COVID-19 patients. Data Sources and Methods: MEDLINE, Scopus, Embase, Cochrane Library, Cochrane COVID-19 study register, European Union Drug Regulating Authorities Clinical Trials Database, and ClinicalTrials.gov were searched to detect observational cohort studies and randomized-controlled clinical trials (RCTs) comparing difference doses of LMWH/F among confirmed COVID-19 cases. Results: Thirty-one eligible studies (6 RCTs and 25 cohort studies) with 11,430 hospitalized patients were included. No association was found between LMWH/F and mortality during the following comparisons: (1) no LMWH/F versus any LMWH/F; (2) prophylactic versus higher than prophylactic LMWH/F; (3) prophylactic versus therapeutic LMWH/F; (4) intermediate versus therapeutic LMWH/F; and (5) lower than therapeutic versus therapeutic LMWH/F. Mortality was higher in patients receiving prophylactic versus intermediate LMWH/F (OR = 2.01; 95% CI: 1.19-3.39). However, this effect was mostly driven by observational data. No associations were detected between the intensity of LMWH/F and the risk of thrombotic and hemorrhagic events, except the lower risk for hemorrhage in patients on prophylactic compared to higher LMWH/F doses. Conclusion: The risk for all-cause mortality was higher in patients receiving prophylactic LMWH/F compared to those on an intermediate dose of LMWH/F, based on observational data. These results should be interpreted in light of the moderate quality and heterogeneity of the included studies. Registration: The study protocol has been registered in the International Prospective Register of Ongoing Systematic Reviews PROSPERO (Registration number: CRD42021229771).

Host immune responses and possible therapeutic targets for viral respiratory tract infections in susceptible populations: a narrative review.

BACKGROUND: Respiratory viruses are associated with significant global morbidity and mortality, as well as socioeconomic factors. Certain conditions and patient groups are more susceptible to develop severe viral respiratory tract infections (RTIs). OBJECTIVES: To summarise the data on deregulated immune pathways that have been associated with increased susceptibility to severe viral RTIs in certain populations. We also describe the commonalities of the defective immune pathways across these susceptible populations that may represent possible targets for future therapeutic or preventative approaches. SOURCES: We conducted free searches in Medline, Scopus, and Google Scholar for studies focusing on potential mechanisms of immune dysfunction that may be associated with severe viral RTIs in susceptible populations with conditions including pregnancy, obesity, diabetes mellitus, hypertension, cardiovascular disease, asthma, chronic obstructive pulmonary disease (COPD), chronic kidney disease, and extremes of age. We considered preclinical/animal data, original human studies, and reviews. CONTENT: Innate and adaptive immune responses become quantitatively and qualitatively compromised in aging, obesity, and diabetes mellitus, with the most pronounced changes affecting T cells. Moreover, immune dysregulation by the so-called inflamm-aging results in chronic low-grade inflammation in such conditions. Increased leptin levels affect the immune system particularly in obesity, while leptin dysregulation plays a role in asthma and COPD pathogenesis. Deficient production of interferon (IFN) type I and III in response to rhinovirus contributes to asthma exacerbations. Similar attenuation of IFN production in response to influenza and rhinovirus has been documented in pregnancy. Dampened type I IFN responses have also been found in diet-induced obese mice and in obese individuals. IMPLICATIONS: Immunosenescence and chronic low-grade inflammation accompanying aging and a variety of chronic conditions, such as diabetes, obesity, asthma, COPD, chronic renal disease, and hypertension, contribute to the poor outcomes observed following viral respiratory infections. Commonly affected pathways may represent potential future therapeutic targets.

Greek BLS Certified Providers' CPR Willingness and Skill Retention During the Pre-Vaccine Covid-19 Pandemic Period. A Survey of the Hellenic Society of Cardiology.

OBJECTIVE: The aim of this study was to evaluate the level of established knowledge regarding cardiopulmonary resuscitation (CPR) during the pre-vaccine Covid-19 pandemic era of certified Basic Life Support (BLS) providers, as well as their attitude towards CPR and their willingness to provide CPR. METHODS: Certified BLS providers from courses held in Athens, Greece, were asked to complete an electronic survey regarding their knowledge of and stance towards performing CPR on victims with confirmed or suspected Covid-19 infection. Their insight on BLS courses was also assessed. Answers were collected during June 2020. RESULTS: Out of 5513 certified providers, 25.53% completed the survey. The majority (83.36%) would provide CPR to a cardiac arrest victim with possible or confirmed Covid-19 infection. Regarding the use of an automated external defibrillator, most respondents anticipated that it is equally safe as in the pre-Covid-19 period (58.24%). A more elementary level of education (p = 0.04) made rescuers more willing to provide CPR. Access to the European Resuscitation Council (ERC) or to the Greek National Public Health Organization (NPHO) guidelines was not correlated to the attitude towards resuscitation. Time since the last BLS seminar had no impact on the rescuers' attitude (p = 0.72). All responders agreed that training in CPR during Covid-19 remains necessary. CONCLUSION: Certified BLS providers maintained their willingness to perform CPR in cardiac arrest victims even during the pre-vaccine, dangerous Covid-19 pandemic period. Knowledge regarding Covid-19 CPR was satisfactory; however, continuous training, focused on the revised algorithms, was considered essential.