The role of viral load in the outcome of patients requiring hospital admission due to influenza is not well established. We aim to assess if there is an association between the viral load and the outcome in hospitalized patients with a confirmed influenza virus infection. A retrospective observational study including all adult patients who were hospitalized in our center with a confirmed influenza virus infection from January to May 2016. Viral load was measured by real-time reverse-transcriptase-polymerase chain reaction (rRT-PCR) cycle threshold (Ct) value on upper respiratory tract samples. Its value was categorized into three groups (low Ct,≤ 20; intermediate Ct,(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) and high Ct, > 30). Two hundred thirty-nine patients were included. Influenza A/ H1N1pdm09 was isolated in 207 cases (86.6%). The mean Ct value was 26.69 ± 5.81. The viral load was higher in the unvaccinated group when compared with the vaccinated patients (Ct 25.17 ± 5.55 vs. 27.58 ± 4.97, p = 0.004). Only 27 patients (11.29%) presented a high viral load. Patients with a high viral load more often showed abnormal findings on chest X-ray (p = 0.015) and lymphopenia (p = 0.097). By contrast, there were no differences between the three groups (according to viral load), in associated pneumonia, respiratory failure, need for mechanical ventilation, sepsis, or in-hospital mortality. Our findings suggest that in patients admitted to the hospital with confirmed influenza virus infection (mostly A/H1N1pdm09), a high viral load is associated with a higher presence of abnormal findings on chest X-ray but not with a significant worse prognosis. In these cases, standardized quantitative PCR could be useful.

Objectives: There is increasing evidence that ferritin is a key marker of macrophage activation, but its potential role in influenza infection remains unexplored. Our aim was to assess whether hyperferritinaemia (ferritin 500 ng/mL) could be a marker of poor prognosis in hospitalized patients with confirmed influenza A infection. Methods: We prospectively recruited all hospitalized adult patients who tested positive for the influenza A rRT-PCR assay performed on respiratory samples in two consecutive influenza periods (2016e17 and 2017e18). Poor outcome was defined as the presence of at least one of the following: respiratory failure, admission to the intensive care unit, or in-hospital mortality. Results: Among 494 patients, 68 (14%) developed poor outcomes; 112 patients (23%) had hyperferritinaemia (39/68, 57% in the poor-outcome group versus 73/426, 17% in the remaining patients, p < 0.0001). Median serum ferritin levels were significantly higher in the subgroup of patients with poor outcomes (609 ng/mL, range 231e967 versus 217 ng/mL, range 140e394, p < 0.0001). In multivariate analysis, hyperferritinaemia was associated with a five-fold increase in the odds ratio of developing poor outcome. After adjusting for classic influenza risk factors, ferritin remained as a significant predictive factor in all exploratory models. Ferritin levels had a good discriminative capacity with an area under the ROC curve of 0.72 (95% confidence interval (CI) 0.65e0.8, p < 0.001) and an overall diagnostic accuracy for predicting poor outcome of 79.3% (95%CI 75.4e82.7%). Conclusions: Serum ferritin may discriminate a subgroup of patients with influenza infection who have a higher risk of developing a poor outcome.

No abstract

Although hematological abnormalities have been described among patients with influenza virus infection, little is known about their impact on the outcome of the patients. The aim of this study was to assess the frequency and clinical impact of severe hematological abnormalities in patients with confirmed influenza virus infection. This was an observational retrospective study including all adult patients with diagnosis of influenza virus infection hospitalized from January to May 2016 in our institution. Influenza virus infection was diagnosed by means of rRT-PCR assay performed on respiratory samples. Poor outcome was defined as a composite endpoint in which at least one of the following criteria had to be fulfilled: (a) respiratory failure, (b) SOFA ≥2, or (c) death. Two hundred thirty-nine patients were included. Applying the HLH-04 criteria for the diagnosis of hemophagocytic syndrome, cytopenias (hemoglobin ≤9 g/dl, platelets <100,000/μl or neutrophils <1,000/μl) were present in 51 patients (21%). Patients with hematological abnormalities showed higher SOFA scores, respiratory failure, septic shock and in-hospital mortality than the remaining patients. The composite endpoint was present in 33.3% in the cytopenias group vs. 13.3% in the group without cytopenias (p=0.001). In a multivariate analysis, variables associated with the composite endpoint were: use of steroids prior to present admission (OR: 0.12; 95% CI: 0.015-0.96, p=0.046), presence of any hematological abnormality (OR: 3.54; 95% CI:1.66-7.51, p= 0.001), and LDH>225 U/l (OR:4.45; CI:1-19.71, p=0.049). Hematological abnormalities are not uncommon among hospitalized patients with influenza virus infection, and they are associated with a poorer outcome.

No abstract