Evaluation of a new, rapid, simple test for the detection of influenza virus.

BACKGROUND: Influenza virus infections are responsible for significant morbidity and mortality in both pediatric and adult populations worldwide. Rapid and accurate diagnosis of influenza is necessary for appropriate patient management during the influenza season and for optimal utilization of anti-influenza therapy. We prospectively tested the accuracy of a simple and rapid diagnostic method. METHODS: Ninety-eight samples (nasal and pharyngeal swabs) from patients with upper respiratory tract infection symptoms who presented to primary healthcare centres in Barcelona (Spain) were prospectively analyzed. The samples were collected as part of influenza surveillance program. Samples that had enough volume to make the new test after aliquoting the amount needed to perform routine tests were included. None of the samples were pre-selected as a result of their status in relation to influenza virus. Samples were analyzed by in-house real-time PCR and Alere i Influenza A & B (Alere i), which uses isothermal amplification of nucleic acids for the qualitative detection of influenza A and B in nasal swabs transported in viral transport media. The two techniques were compared by positive percent agreement (PPA) and negative percent agreement (NPA). Statistical analysis was performed with Stata. RESULTS: Of the 98 samples analysed 90 were concordant; 46 (46.9%) were positive and 44 (44.9%) were negative. Five samples showed invalid results with the Alere i test and could be not re-tested due to insufficient sample volume and were not included in the final statistical analysis. In the 93 remaining samples, the Alere i test showed 97% of accuracy having correctly classified 90 samples. We obtained discordant results in 3 samples (3%). The PPA was 93.8% for influenza A and 94.1% for influenza B, and NPA was 100% for influenza A and influenza B virus. In addition, the Alere i was very rapid (15 minutes or less) and extremely easy to use. CONCLUSIONS: The Alere i test provided a good correlation compared to the real-time PCR test for the diagnosis of influenza. Since this method can be performed in minutes, it allows immediate, accurate clinical decisions to prescribe appropriate antiviral treatment or isolation of patients.

Influenza vaccine effectiveness assessment through sentinel virological data in three post-pandemic seasons.

Influenza vaccination aims at reducing the incidence of serious disease, complications and death among those with the most risk of severe influenza disease. Influenza vaccine effectiveness (VE) through sentinel surveillance data from the PIDIRAC program (Daily Acute Respiratory Infection Surveillance of Catalonia) during 2010-2011, 2011-2012, and 2012-2013 influenza seasons, with three different predominant circulating influenza virus (IV) types [A(H1N1)pdm09, A(H3N2) and B, respectively] was assessed. The total number of sentinel samples with known vaccination background collected during the study period was 3173, 14.7% of which had received the corresponding seasonal influenza vaccine. 1117 samples (35.2%) were positive for IV. A retrospective negative case control design was used to assess vaccine effectiveness (VE) for the entire period and for each epidemic influenza season. An overall VE of 58.1% (95% CI:46.8-67) was obtained. Differences in VE according to epidemic season were observed, being highest for the 2012-2013 season with predominance of IV type B (69.7% ;95% CI:51.5-81) and for the 2010-2011 season, with predominance of the A(H1N1)pdm09 influenza virus strain (67.2% ;95%CI:49.5-78.8) and lowest for the 2011-2012 season with A(H3N2) subtype predominance (34.2% ;95%CI:4.5-54.6). Influenza vaccination prevents a substantial number of influenza-associated illnesses. Although vaccines with increased effectiveness are needed and the search for a universal vaccine that is not subject to genetic modifications might increase VE, nowadays only the efforts to increase vaccination rates of high-risk population and healthcare personnel let reduce the burden of influenza and its complications.

Viral etiology of mumps-like illnesses in suspected mumps cases reported in Catalonia, Spain.

We investigated the etiology of reported sporadic suspected mumps cases with a negative RT-PCR result for the mumps virus in the Barcelona-South region in 2007-2011. Samples from mumps virus-negative patients presenting unilateral or bilateral parotitis or other salivary gland swelling were tested for Epstein-Barr virus (EBV) by real-time PCR and for respiratory viruses by two multiplex-PCR-based assays to detect parainfluenza virus (PIV) 1-4, influenza virus (InV) A, B and C, respiratory syncytial virus (RSV), enterovirus, coronavirus 229E, coronavirus OC43, and rhinovirus. 101 samples were analyzed in persons aged 8 months to 50 years. Oral samples were collected on the first day of glandular swelling in 53 patients (52.5%), and on the first two days in 74 patients (73.3%). Viruses were detected in 52 (51.5%) of samples: one virus (25 EBV, 8 PIV3, 4 adenovirus, 4 PIV2, 1 PIV1, 1 InVA, and 1 enterovirus) was detected in 44 patients (84.6%), two viruses in 7 patients, and three viruses in one patient. In 58 patients (57.5%) whose sample was collected in the first 2 days after onset of parotitis and had received two doses of MMR vaccine and in 15 patients (14.8%) whose sample was collected on the first day, it is very likely that the cause was not the mumps virus. This would mean that 72.3% (73/101) of the reported sporadic suspected mumps cases were not mumps cases. The timing of oral-sample collection is crucial to correctly interpret the negative results for mumps virus RNA, especially when suspected cases occur in vaccinated persons.

Influenza C virus surveillance during the first influenza A (H1N1) 2009 pandemic wave in Catalonia, Spain.

Although particular attention is paid to influenza A and B virus isolates during influenza surveillance, influenza C virus (FLUCV) coexisted during the first influenza A (H1N1) 2009 pandemic wave during the 2009-2010 season. From 27 April 2009 to 9 May 2010, 12 strains of FLUCV were detected in specimens collected from 1713 nonhospitalized patients with upper respiratory tract illness using a molecular method. Half of the patients with FLUCV infection were older than 14 years. The most frequent symptoms were cough and fever, similar to other viral respiratory infections. Phylogenetic analysis of the hemagglutinin-esterase gene revealed that the strains belonged to the C/Kanagawa/1/76-related and C/Sao Paulo/378/82-related lineages, demonstrating their co-circulation in Catalonia. In addition to regular virological surveillance that provides information about the incidence and the exact role of FLUCV in acute viral respiratory infections in the general population, the genetic lineage identification offers additional data for epidemiological purposes.

Differences in sentinel influenza confirmed incidence rates and clinical presentation of influenza virus: 2008-09 seasonal vs 2009-10 pandemic influenza.

The Influenza sentinel surveillance network of Catalonia (PIDIRAC) allows for the study of circulating influenza virus (IV). The aim of this work was to assess differences between two influenza seasons, the 2008-2009 A(H3N2) season and the 2009-2010 season with predominance of pandemic influenza virus circulation. Incidence rate (IR) of confirmed influenza illness were calculated for both periods and age group. Clinical presentation features by age group (0-4,5-14,15-64 and > 64 y.o.) were studied and compared for both seasons. Statistical significance of proportion differences assessed by statistic z and Mantel Hanzel's Woolf test. The level of statistical significance was established at α=0.05. In both seasons studied, the 5-14 y.o. age group presented the highest confirmed influenza IR and highest presentation of cephalalgia as a symptom in the pandemic A(H1N1)2009 season. In conclusion, the significant burden of influenza, both seasonal and pandemic , on children should encourage upgrading vaccination coverage in these age groups and especially for those included in risk groups for whom yearly vaccination is recommended.

D225G mutation in the hemagglutinin protein found in 3 severe cases of 2009 pandemic influenza A (H1N1) in Spain.

From 27 April to 16 December 2009, we analyzed the hemagglutinin gene sequence of 2009 pandemic influenza A (H1N1) virus in 189 respiratory specimens. We only found the D225G mutation in 3 severe cases. However, it was not found in samples from other cases with or without clinical criteria of severity. The biologic significance of this mutation remains still unclear.

Double (V27A/S31N) mutant 2009 pandemic influenza A (H1N1) virus isolated from adamantane non-treated inmunocompetent child.

We report the first strain of 2009 pandemic influenza A (H1N1) virus with V27A mutation in addition to S31N substitution in M2 gen. It was isolated from adamantane non-treated child.