Rapid Point-of-Care Influenza Testing for Patients in German Emergency Rooms - A Cost-Benefit Analysis

Clinical manifestations of influenza and performance of rapid influenza diagnostic test: A university hospital setting

BACKGROUND

Rapid influenza diagnostic test (RIDT) is a diagnostic tool that detects the influenza virus nucleoprotein antigen. The RIDT is widely used in clinical practice because it is simple and cost-effective, and provides results within 10-15 minutes.

OBJECTIVE

We aimed at evaluating the sensitivity and specificity of the Sofia® RIDT compared with the Luminex® multiplex polymerase chain reaction (PCR). The other goal was to determine the predicting factors for diagnosing influenza among individuals with influenza-like illness (ILI).

METHOD

Patients with ILI who had the results of both tests were retrospectively reviewed. We determined the performances of the RIDT.

RESULTS

A total of 473 patients were included with a median age of 58 (interquartile range 41-74) years. Of these, 47.1% were male, and 16.2% were diagnosed with influenza by the RIDT or RT-PCR's positive test. For influenza A, the RIDT showed a sensitivity of 76.3% (95% confidence interval [CI] 59.8-88.6) and a specificity of 97.9% (95% CI 96.1-99.0), whereas for influenza B, it showed a sensitivity of 47.1% (95% CI 23.0-72.2) and a specificity of 97.1% (95% CI 95.2-98.5). Patients with influenza were more likely to present with fever (81.8% vs 63.1%), cough (81.8% vs 66.1%), and rhinorrhea (41.6% vs 26.5%) compared to those without influenza (P < 0.05, all), and had a higher proportion of pneumonia (19.5% vs 10.6%, P = 0.029) and acute respiratory distress syndrome (5.2% vs 1.5%, P = 0.063). The predicting factors for influenza among patients presented with ILI were cough (odds ratio [OR] 2.77; 95% CI 0.21-0.81, P = 0.010), rhinorrhea (OR 1.87; 95% CI 1.03-3.36, P = 0.037), and higher body temperature (OR 1.64; 95% CI 1.23-2.19, P = 0.001).

CONCLUSIONS

The sensitivity of the RIDT for the diagnosis of influenza is fair in contrast to the specificity. Among patients with ILI, cough, rhinorrhea, and higher body temperature might be factors for predicting influenza.

Clinical impact of nosocomial infection with pandemic influenza A (H1N1) 2009 in a respiratory ward in Guangzhou

Background

Nosocomial outbreaks of pandemic influenza A (H1N1) 2009 virus [A(H1N1)pdm09] easily develop due to its high transmissibility. This study aimed to investigate the clinical impacts of a nosocomial outbreak of A(H1N1)pdm09 between 21 January and 17 February 2016.

Methods

Patients who developed influenza-like illness (ILI) more than 48 hours after hospitalization in the index ward were enrolled as suspected patients, defined as group A and quarantined. Patients in other wards were defined as group B. A phylogenetic tree was constructed to determine the origins of the hemagglutinin and neuraminidase genes.

Results

After the implementation of an infection control measure bundle, the outbreak was limited to eight patients with ILIs in group A. Nasal swabs from seven patients were positive for A(H1N1)pdm09. All the patients recovered after treatment. Prolonged viral shedding was observed in a patient with bronchiectasis and Penicillium marneffei infection. Compared to the expected duration of hospitalization in patients without fever, those with fever had a median 7-day delay in discharge and a mean excess cost of 3,358 RMB. The four influenza strains identified were genetically identical to the A/California/115/2015 strain. Six of the 54 patients in group B who underwent bronchoscopy developed transient fever. These patients were hospitalized in various wards of the hospital and recovered after a short-term course of empirical antibiotics.

Conclusions

After the implementation of infection control measures, the nosocomial A(H1N1)pdm09 outbreak was rapidly contained; infected patients had a delay in discharge and excess costs, but no deaths occurred.