Katelijn Vandemaele

Risk Factors for Severe Outcomes following 2009 Influenza A (H1N1) Infection: A Global Pooled Analysis

This study analyzes data from 19 countries (from April 2009 to Jan 2010), comprising some 70,000 hospitalized patients with severe H1N1 infection, to reveal risk factors for severe pandemic influenza, which include chronic illness, cardiac disease, chronic respiratory disease, and diabetes.

Influenza seasonality in the tropics and subtropics: when to vaccinate?

Background The timing of the biannual WHO influenza vaccine composition selection and production cycle has been historically directed to the influenza seasonality patterns in the temperate regions of the northern and southern hemispheres. Influenza activity, however, is poorly understood in the tropics with multiple peaks and identifiable year-round activity. The evidence-base needed to take informed decisions on vaccination timing and vaccine formulation is often lacking for the tropics and subtropics. This paper aims to assess influenza seasonality in the tropics and subtropics. It explores geographical grouping of countries into vaccination zones based on optimal timing of influenza vaccination. Methods Influenza seasonality was assessed by different analytic approaches (weekly proportion of positive cases, time series analysis, etc.) using FluNet and national surveillance data. In case of discordance in the seasonality assessment, consensus was built through discussions with in-country experts. Countries with similar onset periods of their primary influenza season were grouped into geographical zones. Results The number and period of peak activity was ascertained for 70 of the 138 countries in the tropics and subtropics. Thirty-seven countries had one and seventeen countries had two distinct peaks. Countries near the equator had secondary peaks or even identifiable year-round activity. The main influenza season in most of South America and Asia started between April and June. The start of the main season varied widely in Africa (October and December in northern Africa, April and June in Southern Africa and a mixed pattern in tropical Africa). Eight “influenza vaccination zones” (two each in America and Asia, and four in Africa and Middle East) were defined with recommendations for vaccination timing and vaccine formulation. The main limitation of our study is that FluNet and national surveillance data may lack the granularity to detect sub-national variability in seasonality patterns. Conclusion Distinct influenza seasonality patterns, though complex, could be ascertained for most countries in the tropics and subtropics using national surveillance data. It may be possible to group countries into zones based on similar recommendations for vaccine timing and formulation.

Avian influenza A(H7N9) and the closure of live bird markets.

WPSAR Vol 4, No 2, 2013 | doi: 10.5365/wpsar.2013.4.2.008 www.wpro.who.int/wpsar 1 a Division of Health Securities and Emergencies, World Health Organization Regional Offi ce for Western Pacifi c, Manila, Philippines. b World Health Organization, Geneva, Switzerland. c Emerging Diseases Surveillance and Response, World Health Organization, China Offi ce, Beijing, China. d Chinese Center for Disease Control and Prevention, Beijing, China. * Members of the World Health Organization Regional Offi ce for the Western Pacifi c Event Management Team: Nyka Alexander, Steve Bice, Joy Rivaca Caminade, Xavier Dufrenot, Emily Jane Fearnley, Alice Ruth Foxwell, Nori Isoda, Michelle McPherson, Zu Rongqiang, Tomoe Shimada. Submitted: 8 May 2013; Published: 21 May 2013 doi: 10.5365/wpsar.2013.4.2.008 On 31 March 2013, the National Health and Family Planning Commission, China notified the World Health Organization of three cases of human infection with avian influenza A(H7N9) from Shanghai and Anhui.1 By 8 May, 131 cases, including 26 deaths, had been notified from 11 provinces/ municipalities.1,2 The majority (81%) of reported cases were from Shanghai municipality and Zhejiang and Jiangsu provinces. Available data indicate that more than three quarters of cases (59/77, 76%) had recent exposure to animals. Among these, 58% (34/59) had direct contact with chickens and 64% (38/59) visited a live bird market (LBM).3 Provincial and national authorities in China have collected more than 80 000 samples from LBMs, poultry slaughter houses, poultry farms, wild bird habitats, pig slaughter houses and their environments. As of 7 May, 50 samples were positive for avian influenza A(H7N9): 39 samples from poultry from LBMs in Anhui, Jiangsu, Jiangxi, Guangdong, Shanghai and Zhejiang provinces (26 chickens, three ducks, four pigeons, six unknown) and 11 environmental samples from LBMs in Shanghai, Henan and Shandong provinces.4 None of the samples from poultry farms or pigs were positive.5

Improving influenza surveillance in sub-Saharan Africa

PROBLEM Little is known about the burden of influenza in sub-Saharan Africa. Routine influenza surveillance is key to getting a better understanding of the impact of acute respiratory infections on sub-Saharan African populations. APPROACH A project known as Strengthening Influenza Sentinel Surveillance in Africa (SISA) was launched in Angola, Cameroon, Ghana, Nigeria, Rwanda, Senegal, Sierra Leone and Zambia to help improve influenza sentinel surveillance, including both epidemiological and virological data collection, and to develop routine national, regional and international reporting mechanisms. These countries received technical support through remote supervision and onsite visits. Consultants worked closely with health ministries, the World Health Organization, national influenza laboratories and other stakeholders involved in influenza surveillance. LOCAL SETTING Influenza surveillance systems in the target countries were in different stages of development when SISA was launched. Senegal, for instance, had conducted virological surveillance for years, whereas Sierra Leone had no surveillance activity at all. RELEVANT CHANGES Working documents such as national surveillance protocols and procedures were developed or updated and training for sentinel site staff and data managers was organized. LESSONS LEARNT Targeted support to countries can help them strengthen national influenza surveillance, but long-term sustainability can only be achieved with external funding and strong national government leadership.

Seasonal influenza vaccine policy, use and effectiveness in the tropics and subtropics – a systematic literature review

The evidence needed for tropical countries to take informed decisions on influenza vaccination is scarce. This article reviews policy, availability, use and effectiveness of seasonal influenza vaccine in tropical and subtropical countries.

Establishing a national influenza sentinel surveillance system in a limited resource setting, experience of Sierra Leone.

BackgroundAcute respiratory infections remain a leading cause of morbidity and mortality in Sierra Leone; however, similar to other African countries, little is known regarding the contribution of influenza. Routine influenza surveillance is thus a key element to improve understanding of the burden of acute respiratory infections in Africa. In 2011, the World Health Organization (WHO) funded the Strengthening Influenza Sentinel Surveillance in Africa (SISA) project with the goal of developing and strengthening influenza surveillance in eight countries in sub-Saharan Africa, including Sierra Leone. This paper describes the process of establishing a functional Influenza Sentinel Surveillance (ISS) system in Sierra Leone, a post-conflict resource-poor country previously lacking an influenza monitoring system.MethodsSierra Leone utilized a systematic approach, including situational assessment, selection of sentinel sites, preparation of implementation plan, adaptation of the standard operating procedures, supervision and training of staff, and monitoring of influenza surveillance activities. The methods used in Sierra Leone were adapted to its specific context, using the Integrated Disease Surveillance and Response (IDSR) strategy as a platform for establishing ISS.ResultsThe ISS system started functioning in August 2011 with subsequent capacity to contribute surveillance activity data to global influenza databases, FluID and FluNet, demonstrating a functional influenza surveillance system in Sierra Leone within the period of the WHO SISA project support. Several factors were necessary for successful implementation, including a systematic approach, national ownership, appropriate timing and external support.ConclusionsThe WHO SISA project demonstrated the feasibility of building a functional influenza surveillance system in Sierra Leone, integrated into existing national IDSR system. The ISS system, if sustained long-term, would provide valuable data to determine epidemiological and virological patterns and seasonal trends to assess the influenza disease burden that will ultimately guide national control strategies.

Revision of clinical case definitions: influenza-like illness and severe acute respiratory infection

Abstract 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.

Mejorar la vigilancia de la gripe en el África subsahariana

Introduction Acute respiratory infections are major contributors to morbidity and mortality in Africa, (1) yet the burden of influenza in African countries is still poorly understood. (2,3) In the Afriflu meeting that was held in June 2010 in Marrakesh, Morocco, influenza specialists and public health experts pledged to follow concrete measures to bridge the knowledge gap on the burden of influenza in Africa. (4) One of the key measures recommended was the reinforcement of routine influenza surveillance capacity both from an epidemiological and a virological standpoint. Surveillance data from the African continent has increased substantially in the past five years, but they are still too sparse and inconsistent to allow for a thorough understanding of influenza virus circulation patterns on the continent and their associated morbidity and mortality, or to inform influenza control strategies. Generating robust seasonal influenza surveillance data is a concern both regionally and globally. The 2009 influenza pandemic had highlighted the importance of using a standardized approach and terminology in conducting influenza surveillance activities. In March 2011, the World Health Organization (WHO) held an expert consultation in Geneva, Switzerland, to develop global standards for influenza surveillance. (5) The specific aims of the meeting were to update case definitions for influenza-like illness (ILI) and severe acute respiratory infection (SARI) and to provide guidance on creating and maintaining influenza sentinel surveillance systems. To improve regional capacity for surveillance, WHOs Regional Office for Africa developed a regional strategy whereby ILI and SARI were included as priority diseases in the technical guidelines for integrated disease surveillance and response in the African Region, (6) as well as in specific guidelines for influenza sentinel surveillance. WHO selected eight target countries in sub-Saharan Africa--Angola, Cameroon, Ghana, Nigeria, Rwanda, Senegal, Sierra Leone and Zambia --to receive support in starting or strengthening influenza sentinel surveillance and in improving data sharing nationally, regionally and globally via WHOs FluNet and Fluid databases (Box 1). (7,8) This endeavour, known as the Strengthening Influenza Sentinel Surveillance in Africa (SISA) project, was implemented by the Agence de Medecine Preventive in close collaboration with WHO. Project objectives and methods The primary objective of the SISA project was to develop or strengthen influenza sentinel surveillance systems in line with WHO standards in selected sub-Saharan African countries. Countries were chosen in a way intended to synergistically enhance the surveillance capacity development activities being supported in the region by other organizations. The ultimate goal was to generate a representative network of functional surveillance systems that would provide a reasonably accurate picture of influenza activity on the African continent. Countries were given support in the development of routine influenza data collection, analysis and reporting mechanisms at the national and international level, the latter via global databases. Box 1. World Health Organization (WHO) global influenza surveillance databases FluNet and FluiD FluNet--a global tool for influenza virological surveillance FluNet is a global tool for influenza virological surveillance. The virological data entered into FluNet (e.g. number of influenza viruses detected by subtype) are important for tracking the movement of viruses globally and interpreting global epidemiological patterns. FluNet data are publically available and provided in realtime. Results are presented in various formats including tables, maps and graphs. Data are provided remotely by National Influenza Centers (NICs) of the Global Influenza Surveillance and Response System (GISRS) and other national influenza reference laboratories collaborating actively with GISRS, or are uploaded from WHO regional databases. …