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The formulation of accurate clinical case definitions is an integral part of an effective process of public health surveillance. Although such definitions should, ideally, be based on a standardized and fixed collection of defining criteria, they often require revision to reflect new knowledge of the condition involved and improvements in diagnostic testing. Optimal case definitions also need to have a balance of sensitivity and specificity that reflects their intended use. After the 2009- 2010 H1N1 influenza pandemic, the World Health Organization (WHO) initiated a technical consultation on global influenza surveillance. This prompted improvements in the sensitivity and specificity of the case definition for influenza--i.e. a respiratory disease that lacks uniquely defining symptomology. The revision process not only modified the definition of influenza-like illness, to Include a simplified list of the criteria shown to be most predictive of influenza infection, but also clarified the language used for the definition, to enhance interpretability. To capture severe cases of influenza that required hospitalization, a new case definition was also developed for severe acute respiratory infection in all age groups. The new definitions have been found to capture more cases without compromising specificity. Despite the challenge still posed In the clinical separation of influenza from other respiratory infections, the global use of the new WHO case definitions should help determine global trends in the characteristics and transmission of influenza viruses and the associated disease burden. La formulation de definitions precises de cas cliniques fait partie integrente d'un processus efncace de surveillance de la sante publique. Alors que ees definitions devraient, dans l'ideal, s'appuyer sur un ensemble standardise et fixe de criteres de definition, elles necessitent souvent une revision pour tenir compte des nouvelles connaissances relatives a la maladie concernee et des ameliorations apportees aux tests diagnostiques. Pour etre optimales, les definitions de cas doivent aussi etablir un equilibre entre sensibilite et specificite qui reflete leur utilisation aux fins prevues. A la suite de la pandemie de grippe H1N1 de 2009-2010, l'Organisation mondiale de la Sante (OMS) a lance une consultation technique sur la surveillance mondiale de la grippe. Cela a conduit a des ameliorations concernant la sensibilite et la specificite de la definition de cas pour la grippe--c'est-a-dire une maladie respiratoire dont seule la symptomatologie reste a definir. Le processus de revision n'a pas seulement modifie la definition du syndrome de type grippal pour indure une liste simplifiee des criteres le mieux a meme de predire une infection grippale, il a egalement permis de clarifier le langage utilise dans la definition pour en ameliorer Interpretation. Par ailleurs, afin de tenir compte des cas severes de grippe qui necessitaient une hospitalisation, une nouvelle definition de cas a ete introduite concernant l'infection aigue severe des voies respiratoires dans tous les groupes d'age. Il a ete constate que les nouvelles definitions refletaient davantage de cas, sans pour autant compromettre la specificite. S'il est vral que la distinction clinique de la grippe des autres infections respiratoires continue de poser probleme, l'utilisation mondiale des nouvelles definitions de cas de l'OMS devralt permettre de degager des tendances mondiales concernant les caracteristiques et la transmission des virus grippaux ainsi que la charge de morbidite qui leur est associee. La elaboracion de definiciones precisas de los casos clinicos es una parte fundamental de un proceso efectivo de la vigilancia de la salud publica. Aunque tales definiciones deberian, idealmente, estar basadas en una recopilacion estandarizada y fija de criterios de definicion, a menudo necesitan una revision para reflejar el nuevo conocimiento de la enfermedad existente y las mejoras en las pruebas de diagnostico. Las definiciones optimas de los casos tambien deben tener un equilibrio entre sensibilidad y especificidad que refleje su uso previsto. Despues de la pandemia de gripe H1N1 en 2009-2010, la Organizacion Mundial de la Salud (OMS) inicio una consulta tecnica para la vigilancia mundial de la gripe. Esto dio lugar a mejoras en la sensibilidad y la especificidad de las definiciones de los casos de gripe, es decir, una enfermedad respiratoria que carece de una sintomatologia definitoria singular. El proceso de revision no solo modifico la definicion de las enfermedades similares a la gripe para incluir una lista simplificada de los criterios que demostraron ser mas predictivos de la infeccion por gripe, sino que tambien aclaro el lenguaje utilizado para la definicion, con el fin de mejorar su interpretacion. Para englobar los casos graves de gripe que requirieron hospitalizacion, tambien se desarrollo una nueva definicion de los casos de la infeccion respiratoria aguda grave en todos los grupos de edad. Se ha descubierto que las nuevas definiciones engloban mas casos sin comprometer la especificidad. A pesar del desafio que todavia plantea la separacion clinica de la gripe de otras infecciones respiratorias, el uso global de las nuevas definiciones de los casos de la OMS deberia ayudar a determinar las tendencias mundiales en las caracteristicas y transmision de los virus de la gripe y la carga de la enfermedad asociada., Introduction Case definitions form an important part of standardized systems for public health surveillance. They can be used in the reporting of the conditions under surveillance, the monitoring of geographical [...]

This report summarizes the chronology, epidemiology and virology of the 2014-2015 influenza season in the temperate regions of the northern hemisphere, covering influenza activity data collected from October 2014 until [...]

Background: External quality assessments (EQAs) for the molecular detection of respiratory syncytial virus (RSV) are necessary to ensure the provision of reliable and accurate results. One of the objectives of the pilot of the World Health Organization (WHO) Global RSV Surveillance, 2016‐2017, was to evaluate and standardize RSV molecular tests used by participating countries. This paper describes the first WHO RSV EQA for the molecular detection of RSV. Methods: The WHO implemented the pilot of Global RSV Surveillance based on the WHO Global Influenza Surveillance and Response System (GISRS) from 2016 to 2018 in 14 countries. To ensure standardization of tests, 13 participating laboratories were required to complete a 12 panel RSV EQA prepared and distributed by the Centers for Disease Control and Prevention (CDC), USA. The 14th laboratory joined the pilot late and participated in a separate EQA. Laboratories evaluated a RSV rRT‐PCR assay developed by CDC and compared where applicable, other Laboratory Developed Tests (LDTs) or commercial assays already in use at their laboratories. Results: Laboratories performed well using the CDC RSV rRT‐PCR in comparison with LDTs and commercial assays. Using the CDC assay, 11 of 13 laboratories reported correct results. Two laboratories each reported one false‐positive finding. Of the laboratories using LDTs or commercial assays, results as assessed by Ct values were 100% correct for 1/5 (20%). With corrective actions, all laboratories achieved satisfactory outputs. Conclusions: These findings indicate that reliable results can be expected from this pilot. Continued participation in EQAs for the molecular detection of RSV is recommended. [ABSTRACT FROM AUTHOR]

Four World Health Organization (WHO) Collaborating Centres for Reference and Research on Influenza and one WHO Collaborating Centre for the Surveillance, Epidemiology and Control of Influenza (WHO CCs) assessed antiviral susceptibility of 14,330 influenza A and B viruses collected by WHO-recognized National Influenza Centres (NICs) between May 2015 and May 2016. Neuraminidase (NA) inhibition assay was used to determine 50% inhibitory concentration (IC 50 ) data for NA inhibitors (NAIs) oseltamivir, zanamivir, peramivir and laninamivir. Furthermore, NA sequences from 13,484 influenza viruses were retrieved from public sequence databases and screened for amino acid substitutions (AAS) associated with reduced inhibition (RI) or highly reduced inhibition (HRI) by NAIs. Of the viruses tested by WHO CCs 93% were from three WHO regions: Western Pacific, the Americas and Europe. Approximately 0.8% (n = 113) exhibited either RI or HRI by at least one of four NAIs. As in previous seasons, the most common NA AAS was H275Y in A(H1N1)pdm09 viruses, which confers HRI by oseltamivir and peramivir. Two A(H1N1)pdm09 viruses carried a rare NA AAS, S247R, shown in this study to confer RI/HRI by the four NAIs. The overall frequency of A(H1N1)pdm09 viruses containing NA AAS associated with RI/HRI was approximately 1.8% (125/6915), which is slightly higher than in the previous 2014-15 season (0.5%). Three B/Victoria-lineage viruses contained a new AAS, NA H134N, which conferred HRI by zanamivir and laninamivir, and borderline HRI by peramivir. A single B/Victoria-lineage virus harboured NA G104E, which was associated with HRI by all four NAIs. The overall frequency of RI/HRI phenotype among type B viruses was approximately 0.6% (43/7677), which is lower than that in the previous season. Overall, the vast majority (>99%) of the viruses tested by WHO CCs were susceptible to all four NAIs, showing normal inhibition (NI). Hence, NAIs remain the recommended antivirals for treatment of influenza virus infections. Nevertheless, our data indicate that it is prudent to continue drug susceptibility monitoring using both NAI assay and sequence analysis. [ABSTRACT FROM AUTHOR]

The World Health Organization (WHO) Collaborating Centres for Reference and Research on Influenza (WHO CCs) tested 13,312 viruses collected by WHO recognized National Influenza Centres between May 2014 and May 2015 to determine 50% inhibitory concentration (IC 50 ) data for neuraminidase inhibitors (NAIs) oseltamivir, zanamivir, peramivir and laninamivir. Ninety-four per cent of the viruses tested by the WHO CCs were from three WHO regions: Western Pacific, the Americas and Europe. Approximately 0.5% (n = 68) of viruses showed either highly reduced inhibition (HRI) or reduced inhibition (RI) (n = 56) against at least one of the four NAIs. Of the twelve viruses with HRI, six were A(H1N1)pdm09 viruses, three were A(H3N2) viruses and three were B/Yamagata-lineage viruses. The overall frequency of viruses with RI or HRI by the NAIs was lower than that observed in 2013–14 (1.9%), but similar to the 2012–13 period (0.6%). Based on the current analysis, the NAIs remain an appropriate choice for the treatment and prophylaxis of influenza virus infections. [ABSTRACT FROM AUTHOR]

In February the World Health Organisation (WHO) recommends influenza viruses to be included in influenza vaccines for the forthcoming winter in the Northern Hemisphere. These recommendations are based on data collected by National Influenza Centres (NICs) through the WHO Global Influenza Surveillance and Response System (GISRS) and a more detailed analysis of representative and potential antigenically variant influenza viruses from the WHO Collaborating Centres for Influenza (WHO CCs) and Essential Regulatory Laboratories (ERLs). This article provides a detailed summary of the antigenic and genetic properties of viruses and additional background data used by WHO experts during development of the recommendations of the 2013-2014 Northern Hemisphere influenza vaccine composition. [ABSTRACT FROM AUTHOR]

Four World Health Organization (WHO) Collaborating Centres for Reference and Research on Influenza and one WHO Collaborating Centre for the Surveillance, Epidemiology and Control of Influenza (WHO CCs) tested 10,641 viruses collected by WHO-recognized National Influenza Centres between May 2013 and May 2014 to determine 50% inhibitory concentration (IC 50 ) data for neuraminidase inhibitors (NAIs) oseltamivir, zanamivir, peramivir and laninamivir. In addition, neuraminidase (NA) sequence data, available from the WHO CCs and from sequence databases ( n = 3206), were screened for amino acid substitutions associated with reduced NAI susceptibility. Ninety-five per cent of the viruses tested by the WHO CCs were from three WHO regions: Western Pacific, the Americas and Europe. Approximately 2% ( n = 172) showed highly reduced inhibition (HRI) against at least one of the four NAIs, commonly oseltamivir, while 0.3% ( n = 32) showed reduced inhibition (RI). Those showing HRI were A(H1N1)pdm09 with NA H275Y ( n = 169), A(H3N2) with NA E119V ( n = 1), B/Victoria-lineage with NA E117G ( n = 1) and B/Yamagata-lineage with NA H273Y ( n = 1); amino acid position numbering is A subtype and B type specific. Although approximately 98% of circulating viruses tested during the 2013–2014 period were sensitive to all four NAIs, a large community cluster of A(H1N1)pdm09 viruses with the NA H275Y substitution from patients with no previous exposure to antivirals was detected in Hokkaido, Japan. Significant numbers of A(H1N1)pdm09 NA H275Y viruses were also detected in China and the United States: phylogenetic analyses showed that the Chinese viruses were similar to those from Japan, while the United States viruses clustered separately from those of the Hokkaido outbreak, indicative of multiple resistance-emergence events. Consequently, global surveillance of influenza antiviral susceptibility should be continued from a public health perspective. [ABSTRACT FROM AUTHOR]

Emergence of influenza viruses with reduced susceptibility to neuraminidase inhibitors (NAIs) is sporadic, often follows exposure to NAIs, but occasionally occurs in the absence of NAI pressure. The emergence and global spread in 2007/2008 of A(H1N1) influenza viruses showing clinical resistance to oseltamivir due to neuraminidase (NA) H275Y substitution, in the absence of drug pressure, warrants continued vigilance and monitoring for similar viruses. Four World Health Organization (WHO) Collaborating Centres for Reference and Research on Influenza and one WHO Collaborating Centre for the Surveillance, Epidemiology and Control of Influenza (WHO CCs) tested 11,387 viruses collected by WHO-recognized National Influenza Centres (NIC) between May 2012 and May 2013 to determine 50% inhibitory concentration (IC 50 ) data for oseltamivir, zanamivir, peramivir and laninamivir. The data were evaluated using normalized IC 50 fold-changes rather than raw IC 50 data. Nearly 90% of the 11,387 viruses were from three WHO regions: Western Pacific, the Americas and Europe. Only 0.2% ( n = 27) showed highly reduced inhibition (HRI) against at least one of the four NAIs, usually oseltamivir, while 0.3% ( n = 39) showed reduced inhibition (RI). NA sequence data, available from the WHO CCs and from sequence databases ( n = 3661), were screened for amino acid substitutions associated with reduced NAI susceptibility. Those showing HRI were A(H1N1)pdm09 with NA H275Y ( n = 18), A(H3N2) with NA E119V ( n = 3) or NA R292K ( n = 1) and B/Victoria-lineage with NA H273Y ( n = 2); amino acid position numbering is A subtype and B type specific. Overall, approximately 99% of circulating viruses tested during the 2012–2013 period were sensitive to all four NAIs. Consequently, these drugs remain an appropriate choice for the treatment and prophylaxis of influenza virus infections. [ABSTRACT FROM AUTHOR]

Abstract: In February and September each year the World Health Organisation (WHO) recommends influenza viruses to be included in influenza vaccines for the forthcoming winters in the Northern and Southern Hemispheres respectively. These recommendations are based on data collected by National Influenza Centres (NIC) through the Global Influenza Surveillance and Response System (GISRS) and a more detailed analysis of representative and potential antigenically variant influenza viruses from the WHO Collaborating Centres for Influenza (WHO CCs) and Essential Regulatory Laboratories (ERLs). This article provides a detailed summary of the antigenic and genetic properties of viruses and additional background data used by WHO experts during development of the recommendations for the 2012 Southern Hemisphere influenza vaccine composition. [Copyright &y& Elsevier]