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Background: In Yemen; initial surveillance of COVID-19 focused primarily on patients with symptoms or severe disease, and, as such, the full spectrum of the disease, are not clear that make the epidemiology of COVID-19 is uncertain. To the best of our knowledge, this is the first seroprevalence study done in Yemen to measure the seroprevalence of anti-SARS-CoV-2 antibodies in the general population by sex and age group in Aden, Yemen. Methods: It is a one-time cross-sectional investigation among 2000 participants from all age groups from four districts in Aden at southern Yemen. A multi-stage sampling method used. Data collected by using a well-structured questionnaire and blood sample were collected. Healgen COVID-19 IgG/IgM Rapid Test Cassette was used in all participants. All positive RDT and 14% of the negative RDTs underwent ELISA test (WANTAI SARS-CoV-2 Ab Elisa Kit). Results: A 549 out of 2001 participants were RDT positive and proved by ELISA giving the prevalence of COVID-19 infection to 27·4% and specifically the prevalence of IgG was 25%. The prevalence of asymptomatic COVID-19 infection in all the study group was 7·9%. The highest prevalence was observed in Al-Mansurah district (33·4%). Regarding socio-demographic factors females, housewives and history of contact with COVID-19 patients have significant higher prevalence rates (32%, 31% and 39% respectively). Interpretation: high prevalence of SARS-CoV-2 antibodies was reported. Household contacts are the main factors for transmission. Enhancing population immunity is recommended by introducing COVID-19 vaccine. Funding: The study was funded from WHO/ EMRO. Aden Office Declaration of Interest: None to declare. Ethical Approval: This study was approved by the University of Yemen.

Whole-genome sequencing (WGS) is an approach for studying and analysing the entire genomic sequence of pathogens. It provides the most comprehensive characterization of an organism's genetic make-up. In January 2020, scientists used next-generation sequencing (NGS) as one of several sequencing technologies to study severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and to reveal the first genetic makeup of this new virus only 11 days after the first cluster of cases due to the COVID-19 pandemic was reported. This crucial information was vital to the subsequent rapid development of test kits, vaccines and treatment regimens to respond to the pandemic. The sequencing information, later as the pandemic evolved, became essential for informing public health policies through monitoring and characterization of SARS-CoV-2 variants.

International audience

IntroductionA global reduction in influenza virus activity during the COVID-19 pandemic has been observed, including in the Eastern Mediterranean Region (EMR). However, these changes have not been thoroughly evaluated scientifically in the EMR.ObjectiveWe aim to present data on seasonal influenza activity during the pre-pandemic period (2016–2019) and compare it to the pandemic period (2020–2021) in EM countries.MethodsEpidemiological and virological influenza surveillance data were retrieved from both WHO FluNet and EMFLU networks. Four pre-pandemic analytical periods were used in the comparative analysis. We compiled and calculated weekly aggregated epidemiological data on the number of enrolled patients, number of tested specimens and number of positive influenza specimens.Results19 out of the 22 countries of the EMR have functioning sentinel influenza surveillance systems, and these countries report the influenza data to WHO through FluNet and EMFLU. The number of enrolled patients and tested specimens increased gradually from 51 384 and 50 672, respectively, in 2016–2017 analytical period to 194 049 enrolled patients and 124 697 tested specimens in 2019–2020. A decrease has been witnessed in both enrolled patients and tested specimens in 2020–2021 ‘pandemic period’ (166 576 and 44 764, respectively). By comparing influenza activity of analytical period 2020–2021 with that of 2016–2019 analytical periods, we found that there has been a decrease in influenza positivity rate in the EMR by 89%.ConclusionThe implementation of non-pharmaceutical interventions to control the COVID-19 pandemic may have also impacted the spread of influenza viruses. The low circulation of influenza viruses during 2020–2021 and the associated potential immunity gap may result in increased transmission and severity of post-pandemic influenza seasons. This necessitates high vigilance to continuous data and virus sharing to monitor circulating viruses in a timely fashion to reduce the intensity and severity of future influenza epidemics.

A group convened and led by the Virus Evolution Working Group of the World Health Organization reports on its deliberations and announces a naming scheme that will enable clear communication about SARS-CoV-2 variants of interest and concern.

Influenza viruses with pandemic potential have been detected in humans in the Eastern Mediterranean Region. The Pandemic Influenza Preparedness (PIP) Framework aims to improve the sharing of influenza viruses with pandemic potential and increase access of developing countries to vaccines and other life-saving products during a pandemic. Under the Framework, countries have been supported to enhance their capacities to detect, prepare for and respond to pandemic influenza. In the Eastern Mediterranean Region, seven countries are priority countries for Laboratory and Surveillance (L&S) support: Afghanistan, Djibouti, Egypt, Jordan, Lebanon, Morocco and Yemen. During 2014–2017, US$ 2.7 million was invested in regional capacity-building and US$ 4.6 million directly in the priority countries. Countries were supported to strengthen influenza diagnostic capacities to improve detection, enhance influenza surveillance systems including sentinel surveillance for severe acute respiratory infection and influenza-like illness, and increase global sharing of surveillance data and influenza viruses. This paper highlights the progress made in improving influenza preparedness and response capacities in the Region from 2014 to 2017, and the challenges faced. By 2017, 18 of the 22 countries of the Region had laboratory-testing capacity, 19 had functioning sentinel influenza surveillance systems and 22 had trained national rapid response teams. The number of countries correctly identifying all influenza viruses in the WHO external quality assurance panel increased from 9 countries scoring 100% in 2014 to 15 countries in 2017, and the number sharing influenza viruses with WHO collaborating centres increased by 75% (from eight to 14 countries); more than half now share influenza data with regional or global surveillance platforms. Seven countries have estimated influenza disease burden and seven have introduced influenza vaccination for high-risk groups. Challenges included: protracted complex emergencies faced by nine countries which hindered implementation of influenza surveillance in areas with the most needs, high staff turnover, achieving timely virus sharing and limited utilization of influenza data where they are available to inform vaccine policies or establish threshold values to measure the start and severity of influenza seasons. Keywords: Influenza, Pandemic, PIP framework, Surveillance, Eastern Mediterranean Region

Background: Influenza surveillance systems in the Eastern Mediterranean Region have been strengthened in the past few years and 16 of the 19 countries in the Region with functional influenza surveillance systems report their influenza data to the EMFLU Network. This study aimed to investigate the epidemiology of circulating influenza viruses, causing SARI, and reported to the EMFLU during July 2016 to June 2018. Methods: Data included in this study were collected by 15 countries of the Region from 110 SARI sentinel surveillance sites over two influenza seasons. Results: A total of 40,917 cases of SARI were included in the study. Most cases [20,551 (50.2%)] were less than 5 years of age. Influenza virus was detected in 3995 patients, 2849 (11.8%) were influenza A and 1146 (4.8%) were influenza B. Influenza A(H1N1)pdm09 was the predominant circulating subtype with 1666 cases (58.5%). Other than influenza, respiratory syncytial virus was the most common respiratory infection circulating, with 277 cases (35.9%). Conclusion: Influenza viruses cause a high number of severe respiratory infections in EMR. It is crucial for the countries to continue improving their influenza surveillance capacity in order detect any unusual influenza activity or new strain that may cause a pandemic. Keywords: Influenza, Human, Severe acute respiratory infections, Sentinel surveillance, EMFLU Network, Eastern Mediterranean Region

COVID-19 affected different countries in different ways. Palestine had recorded over 140,000 cases by the end of 2020. The WHO/PNIPH, WHO/EMRO, and the Palestinian MoH carried out a serological survey in Palestine in order to estimate the actual number of COVID-19 infections up to the end of December 2020. A sample stratified by region, district, residence area (urban, rural, and refugee camp), and accounting for gender, was taken from Gaza and the West Bank. Data from participants were also collected, including demographic, socio-economic, and health conditions. The results show that 39% of the Palestinian population (38% of the West Bank and 40% of Gaza) had been infected with COVID-19 by the end of December, almost 10 times the number detected by targeted Rt-PCR testing. Several factors were calculated to be significant such as diabetes, smoking, gender, age, and residence.Summary of findingsThe following table is a summary of all findings presented in this report. The P values in green are below 0.05, which makes the result statistically significant; red is not statistically significant. In binary comparisons (when comparing two numbers), the odds were calculated, meaning how much more likely the presence of seropositivity is if the condition is satisfied. For example, those who were previously diagnosed as COVID-19 positive using Rt PCR were 2.5 times as likely to be seropositive than those who were not diagnosed.

ObjectiveThe primary objectives were to determine the magnitude of COVID-19 infections in the general population and age-specific cumulative incidence, as determined by seropositivity and clinical symptoms of COVID-19, and to determine the magnitude of asymptomatic or subclinical infections.Design, setting and participantsWe describe a population-based, cross-sectional, age-stratified seroepidemiological study conducted throughout Afghanistan during June/July 2020. Participants were interviewed to complete a questionnaire, and rapid diagnostic tests were used to test for SARS-CoV-2 antibodies. This national study was conducted in eight regions of Afghanistan plus Kabul province, considered a separate region. The total sample size was 9514, and the number of participants required in each region was estimated proportionally to the population size of each region. For each region, 31–44 enumeration areas (EAs) were randomly selected, and a total of 360 clusters and 16 households per EA were selected using random sampling. To adjust the seroprevalence for test sensitivity and specificity, and seroreversion, Bernoulli’s model methodology was used to infer the population exposure in Afghanistan.Outcome measuresThe main outcome was to determine the prevalence of current or past COVID-19 infection.ResultsThe survey revealed that, to July 2020, around 10 million people in Afghanistan (31.5% of the population) had either current or previous COVID-19 infection. By age group, COVID-19 seroprevalence was reported to be 35.1% and 25.3% among participants aged ≥18 and 5–17 years, respectively. This implies that most of the population remained at risk of infection. However, a large proportion of the population had been infected in some localities, for example, Kabul province, where more than half of the population had been infected with COVID-19.ConclusionAs most of the population remained at risk of infection at the time of the study, any lifting of public health and social measures needed to be considered gradually.

In 2018, a hepatitis A virus outbreak was identified among internally displaced persons in Syria. Sequence analysis based on the viral protein 1/2A junction revealed that the causative virus belonged to genotype IB. A high displacement rate, deteriorated sanitary and health conditions, and poor water quality likely contributed to this outbreak.

Background: Countries in the World Health Organization (WHO) Eastern Mediterranean Region (EMR) are predisposed to highly contagious, severe and fatal, emerging infectious diseases (EIDs), and re-emerging infectious diseases (RIDs). This paper reviews the epidemiological situation of EIDs and RIDs of global concern in the EMR between 2001 and 2018. Methods: To do a narrative review, a complete list of studies in the field was we prepared following a systematic search approach. Studies that were purposively reviewed were identified to summarize the epidemiological situation of each targeted disease. A comprehensive search of all published studies on EIDs and RIDs between 2001 and 2018 was carried out through search engines including Medline, Web of Science, Scopus, Google Scholar, and ScienceDirect. Results: Leishmaniasis, hepatitis A virus (HAV) and hepatitis E virus (HEV) are reported from all countries in the region. Chikungunya, Crimean Congo hemorrhagic fever (CCHF), dengue fever, and H5N1 have been increasing in number, frequency, and expanding in their geographic distribution. Middle East respiratory syndrome (MERS), which was reported in this region in 2012 is still a public health concern. There are challenges to control cholera, diphtheria, leishmaniasis, measles, and poliomyelitis in some of the countries. Moreover, Alkhurma hemorrhagic fever (AHF), and Rift Valley fever (RVF) are limited to some countries in the region. Also, there is little information about the real situation of the plague, Q fever, and tularemia. Conclusion: EIDs and RIDs are prevalent in most countries in the region and could further spread within the region. It is crucial to improve regional capacities and capabilities in preventing and responding to disease outbreaks with adequate resources and expertise.

The database of the Global Influenza B Study was created by collecting surveillance datasets from each of the participating countries. These national datasets are owned by the participating countries, and thus cannot be shared publicly. Researchers interested in obtaining the country-specific datasets may contact the individuals listed below for further details regarding data access.Argentina (Santa Fe Province): Gabriela Kusznierz (labconi@yahoo.com.ar)Australia: Kate Pennington (kate.pennington@health.gov.au)Bhutan: Sonam Wangchuk (swangchuk@health.gov.bt)Brazil: Cláudio Maierovitch Pessanha Henriques (claudio.henriques@saude.gov.br)Cameroon: Guy Vernet (vernet@pasteur-yaounde.org)Chile: Rodrigo Fasce (rfasce@ispch.cl)China: Feng Luzhao (fenglz@chinacdc.cn)Costa Rica: Alexey W. Clara (wclara@cdc.gov)Ecuador: Alfredo Bruno (alfredobruno@yahoo.es)El Salvador: Alexey W. Clara (wclara@cdc.gov)England: Maria Zambon (maria.zambon@phe.gov.uk)Guatemala: Alexey W. Clara (wclara@cdc.gov)Honduras: Alexey W. Clara (wclara@cdc.gov)Indonesia: Herman Kosasih (hermaninarespond@gmail.com)Italy: Caterina Rizzo (caterina.rizzo@iss.it)Ivory Coast: Herve A. Kadjo (hervekadjo@pasteur.ci)Kazakhstan: Gulzhan Muratbayeva (hnv2@cdc.gov)Kenya: Joshua Mott (zud9@cdc.gov)Madagascar: Jean-Michel Heraud (jmheraud@pasteur.mg)Morocco: Amal Barakat (amal.barakat@yahoo.fr)New Zealand: Sue Huang (sue.huang@esr.cri.nz)Nicaragua: Alexey W. Clara (wclara@cdc.gov)Panama: Alexey W. Clara (wclara@cdc.gov)Portugal: Ana Paula Rodrigues (ana.rodrigues@insa.min-saude.pt)Singapore: Vernon Lee (vernonljm@hotmail.com)South Africa: Cheryl Cohen (cherylc@nicd.ac.za)Turkey: Meral Akcay Ciblak (ciblakm@yahoo.com)Ukraine: Alla Mironenko (miralla@ukr.net)Viet Nam: Le Thi Quinh Mai (lom9@hotmail.com); International audience; BACKGROUND:Influenza disease burden varies by age and this has important public health implications. We compared the proportional distribution of different influenza virus types within age strata using surveillance data from twenty-nine countries during 1999-2014 (N=358,796 influenza cases).METHODS:For each virus, we calculated a Relative Illness Ratio (defined as the ratio of the percentage of cases in an age group to the percentage of the country population in the same age group) for young children (0-4 years), older children (5-17 years), young adults (18-39 years), older adults (40-64 years), and the elderly (65+ years). We used random-effects meta-analysis models to obtain summary relative illness ratios (sRIRs), and conducted meta-regression and sub-group analyses to explore causes of between-estimates heterogeneity.RESULTS:The influenza virus with highest sRIR was A(H1N1) for young children, B for older children, A(H1N1)pdm2009 for adults, and (A(H3N2) for the elderly. As expected, considering the diverse nature of the national surveillance datasets included in our analysis, between-estimates heterogeneity was high (I2>90%) for most sRIRs. The variations of countries' geographic, demographic and economic characteristics and the proportion of outpatients among reported influenza cases explained only part of the heterogeneity, suggesting that multiple factors were at play.CONCLUSIONS:These results highlight the importance of presenting burden of disease estimates by age group and virus (sub)type.

Respiratory syncytial virus (RSV) is a leading cause of mortality and morbidity in young infants, little was known on its circulation types and patterns in Morocco. We conducted a prospective study using sentinel-based influenza surveillance to detect RSV by real time PCR in patients with acute respiratory infections, enrolled during two seasons (2014/15, 2015/16). During September 2014-April 2016, we obtained 1450 specimens, of which 267(18.4%) tested positive for RSV. The proportion of positive RSV infection was higher in patients hospitalized with acute respiratory infection compared to those with mild symptoms in out-patient clinics. The proportion of RSV infection was highest in children aged 0-6 months (45%; P0.001). Higher positivity rate was observed between months of December and March. RSV remains important viral etiological agent causing influenza-like illness and severe acute respiratory infections especially among infants in Morocco. Further surveillance, is required to understand better the risk factors of RSV infections.تجوال الفروس المِخلوي التنفي في المغرب خال الأعوام 2014-2016: نتائج مأخودة من نظام لترصد فروس الإنفلونزا.عبد الرحمان بيموحن، فاطمة الفلكي، حسن احزماض، زكية الركراكي، سميرة بنكروم، آمال بركات.عى الرغم من أن الفروس المخلوي التنفي يعتر أحد الأسباب الرئيسية للوفيات والمراضة في أوساط صغار الرضع فلم يكن معروفاً سوى القليل عن أناط وطُرُز تجواله في المغرب. أجرينا دراسة استباقية باستخدام ترصد الإنفلونزا للكشف عن الفروس المخلوي التنفي بواسطة "تفاعل البلمرة المتسلسل – "الزمن الحقيقي" لدى مرضى مصابن بأمراض تنفسية حادة سُجلوا خال موسمين (2014-2015، 2015-2016). من الفرة ما بن سبتمبر/أيلول 2014 إلى أبريل/نيسان 2016 حصلنا عى 1450 عينة، ثبتت إصابة 267 (%18.4) منها بالفروس المخلوي التنفي. وكانت نسبة العدوى المثبتة بالفروس المخلوي التنفي أعى لدى المرضى الذين أدخلوا إلى المستشفى لإصابتهم بمرض تنفي حاد مقارنة مع المصابن بأعراض خفيفة في العيادات الخارجية. وكانت أعى نسب العدوى بالفروس المخلوي التنفي لدى الأطفال الذين تراوح أعمارهم بن 0 و 6 أشهر (4%45؛ p0.001 ). وقد لوحظ ارتفاع في معدل الإيجابية بن ديسمبر/كانون الأول و مارس/آذار. لا يزال الفروس المخلوي التنفي عاماً سببياً فيروسياً مهاً يسبب أمراضاً شبيهة بالإنفلونزا وأمراضاً تنفسية حادة وخيمة؛ خصوصاً في أوساط الرضع في المغرب. المطلوب مزيد من الترصد - باستخدام النظام الحالي – للوصول إلى فهم أفضل لوبائيات العدوى بالفروس المخلوي التنفي ولعوامل خطر الإصابة به.Circulation du virus respiratoire syncytial au Maroc de 2014 à 2016 : constatations provenant du système de surveillance virologique sentinelle de la grippe.Bien que le virus respiratoire syncytial (VRS) soit l’une des principales causes de mortalité et de morbidité chez les jeunes nourrissons, les modes et les tendances de la circulation de ce virus au Maroc sont très peu connus. Nous avons réalisé une étude prospective en recourant à la surveillance de la grippe basée sur des sites sentinelles dans le but de dépister le VRS grâce à la PCR en temps réel chez des patients souffrant d’infections respiratoires aiguës recrutés au cours de deux saisons (2014-2015 et 2015-2016). De septembre 2014 à avril 2016, nous avons prélevé 1450 échantillons, parmi lesquels 267 (18,4 %) se sont avérés positifs au VRS. La proportion d’infections positives au VRS était plus élevée chez les patients hospitalisés pour une infection respiratoire aiguë que chez les patients en consultation externe souffrant de légers symptômes. Cette proportion était la plus élevée chez les enfants de 0 à 6 mois (45 % ; p0,001). Le pic du taux de positivité a eu lieu de décembre à mars. Le VRS demeure un agent étiologique viral important au Maroc, responsable de syndromes de type grippal et d’infections respiratoires aiguës sévères, en particulier chez les nourrissons. Une surveillance renforcée est indispensable pour mieux comprendre les facteurs de risque des infections à VRS.

We monitored phenotypic and genotypic susceptibility of influenza viruses circulating in Morocco during 2014-2015 to oseltamivir and zanamivir. Throat and nasal swab specimens were collected from outpatients (with influenza-like illness) and inpatients (with severe acute respiratory illness) and tested for influenza viruses using real-time reverse transcription polymerase chain reaction. Positive samples were inoculated in MDCK cells and virus phenotypic susceptibility to neuraminidase inhibitors (NAIs) was assessed using fluorescent NA inhibition. Of 440 specimens, 135 were positive for influenza B Yamagata-like virus, 38 were A(H1N1)pdm09 and 25 were A(H3N2). Sixty influenza B viruses isolated from MDCK cells showed no significant resistance to NAIs. However, two of these strains, B/Morocco/176H/2015 and B/Morocco/CP10/2015, showed reduced susceptibility to oseltamivir. The two influenza B viruses with reduced susceptibility to oseltamivir show that ongoing NAI susceptibility surveillance is essential.اكتشاف فيروسات إنفلونزا B ذات حساسية منخفضة لمثبطات النورامينيداز في المغرب خلال موسم 2014-2015.فاطمة الفلكي، حسن احزماض، عبد الرحمان بيموحن، زكية الركراكي، سميرة بنكروم، يوسف بكري، آمال بركات.تهدف هذه الدراسة إلى رصد خصائص الحساسية المتعلقة بالنمط الظاهري والنمط الجيني لفيروسات الإنفلونزا في المغرب خال موسم 2014-2015 للدوائن المثبطن للنورامينيداز، اوسيلتاميفير وزاناميفر. جُعت العينات (مسحات حلقية أو أنفية) من مرضى خارجين (بأعراض ما يشبه الإنفلونزا) ومرضى داخلين (بأعراض مرض تنفي حاد وخيم)، وفُحصت عينات فيروسات الإنفلونزا A و B باستخدام مقايسات "تفاعل البلمرة المتسلسل – الزمن الحقيقي" في الزمن الحقيقي البسيط. ولُقِّحت العينات الإيجابية عى خلايا مادين- داربي كانن كيدني، وقيمت خصائص حساسية النمط الظاهري للفيروسات المستفرَدة لمثبطات النورامينيداز باستخدام مقايسة تثبيط النورامينيداز المتألق. من أصل 440 عينة كانت 135 (%31) عينة إيجابية لفروس الإنفلونزا B الشبيه بياماجاتا، وكانت 38 (%8) عينة A(H1N1)pdm09، و 25 (%6) عينة كانت A(H3N2)). لقد وجد أن ستين فيروساً من فيروسات الإنفلونزا B التي استُفردت عى MDCK وفُحصت حساسيتها لمثبطات النورامينيداز لم تظهر أي مقاومة تذكر لمثبطات النورامينيداز المتوفرة. واثنان من فيروسات الإنفلونزا B - / B 2015 Morocco/176H/2015 و B/Morocco/CP10/، وهما سالتان استثنائيتان اشتملت عليها فيروسات الإنفلونزا B التي استفردت في MDCK - أظهرا انخفاضاً في الحساسية للأوسيلتاميفير. إن وجود اثنن من فيروسات الإنفلونزا B الجوالة أثناء موسم 2014-2015 في المغرب حساسيتهما منخفضة للأوسيلتاميفير يُظهر أن الترصُّد المستمر للحساسية لمثبطات النورامينيداز أمر ضروري.Maroc : dépistage de virus de la grippe B présentant une sensibilité réduite à l’inhibiteur de la neuraminidase durant la saison 2014-2015.Nous avons surveillé le profil de sensibilité phénotypique et génotypique des virus de la grippe à l’oseltamivir et au zanamivir durant la saison 2014-2015 au Maroc. Des échantillons ont été prélevés (par frottis de gorge ou écouvillonnage du nez) chez des patients externes (présentant un syndrome de type grippal) et chez des patients hospitalisés (présentant une infection respiratoire aiguë sévère). Ils ont été soumis au test de détection des virus de la grippe A et B via la méthode d’analyse RT-PCR simplex en temps réel. Les échantillons positifs ont été inoculés à des cellules rénales canines Madin-Darby (MDCK) et le profil de sensibilité phénotypique des virus isolés aux INA a été évalué au moyen du test d’inhibition de la neuraminidase (NA) par fluorescence. Sur 440 échantillons, 135 (31 %) étaient positifs au virus de la grippe B de type Yamagata, 38 (8 %) à celui de la grippe A(H1N1)pdm09 et 25 (6 %) à celui de la grippe A(H3N2). Soixante virus de la grippe B isolés sur les culture de cellules MDCK et soumis au test de sensibilité aux INA n’ont démontré aucune résistance significative aux INA. Toutefois, deux de ces souches, la B/Maroc/176H/2015 et la B/Maroc/CP10/2015, ont démontré une sensibilité réduite à l’oseltamivir. Les deux virus de la grippe B ayant une sensibilité réduite à l’oseltamivir montrent l’importance d’une surveillance permanente de la sensibilité à l’inhibiteur de la neuraminidase.

Free PMC article: https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/31513690/ We describe the epidemiological characteristics, pattern of circulation, and geographical distribution of influenza B viruses and its lineages using data from the Global Influenza B Study. We included over 1.8 million influenza cases occurred in thirty-one countries during 2000-2018. We calculated the proportion of cases caused by influenza B and its lineages; determined the timing of influenza A and B epidemics; compared the age distribution of B/Victoria and B/Yamagata cases; and evaluated the frequency of lineage-level mismatch for the trivalent vaccine. The median proportion of influenza cases caused by influenza B virus was 23.4%, with a tendency (borderline statistical significance, p = 0.060) to be higher in tropical vs. temperate countries. Influenza B was the dominant virus type in about one every seven seasons. In temperate countries, influenza B epidemics occurred on average three weeks later than influenza A epidemics; no consistent pattern emerged in the tropics. The two B lineages caused a comparable proportion of influenza B cases globally, however the B/Yamagata was more frequent in temperate countries, and the B/Victoria in the tropics (p = 0.048). B/Yamagata patients were significantly older than B/Victoria patients in almost all countries. A lineage-level vaccine mismatch was observed in over 40% of seasons in temperate countries and in 30% of seasons in the tropics. The type B virus caused a substantial proportion of influenza infections globally in the 21st century, and its two virus lineages differed in terms of age and geographical distribution of patients. These findings will help inform health policy decisions aiming to reduce disease burden associated with seasonal influenza. info:eu-repo/semantics/publishedVersion

Background The global burden of pediatric severe respiratory illness is substantial, and influenza viruses contribute to this burden. Systematic surveillance and testing for influenza among hospitalized children has expanded globally over the past decade. However, only a fraction of the data has been used to estimate influenza burden. In this analysis, we use surveillance data to provide an estimate of influenza-associated hospitalizations among children worldwide. Methods and Findings We aggregated data from a systematic review (n = 108) and surveillance platforms (n = 37) to calculate a pooled estimate of the proportion of samples collected from children hospitalized with respiratory illnesses and positive for influenza by age group (, The substantial global burden of influenza infections in children is revealed by Lafond and colleagues. Children in developing countries are 3 times more likely to be hospitalised and treatments vary. This study highlights the need for vaccination programs in the young., Editors' Summary Background Acute lower respiratory infections—bacterial and viral infections of the lungs and airways (the tubes that take oxygen-rich air to the lungs)—are major causes of illness and death in children worldwide. Pneumonia (infection of the lungs) alone is responsible for 15% of deaths among children under five years old and kills nearly one million young children every year. Globally, infections with respiratory syncytial virus and with Streptococcus pneumoniae are associated with about 25% and 18.3%, respectively, of all episodes of severe respiratory infection in young children. Another infectious organism that contributes to the global burden of respiratory disease among children is the influenza virus. Every year, millions of people become infected with this virus, which infects the airways and causes symptoms that include a high temperature, tiredness and weakness, general aches and pains, and a dry chesty cough. Most infected individuals recover quickly, but seasonal influenza outbreaks (epidemics) nevertheless kill about half a million people annually, with the highest burden of severe disease being experienced by elderly people and by children under five years old. Why Was This Study Done? Annual immunization (vaccination) can reduce an individual’s risk of catching influenza, but before a country implements this preventative measure, policymakers need reliable estimates of the burden of influenza in their country. Although such estimates have been calculated for resource-rich countries with temperate climates, where influenza largely occurs in the winter, few estimates of influenza burden are available for resource-limited countries, which has hampered informed consideration of vaccination for influenza prevention in many settings. Recently, however, there has been a global expansion of systematic surveillance and testing for influenza virus among patients admitted to hospital for severe respiratory infection. Here, the researchers use this expanded surveillance data to provide an estimate of influenza-associated hospitalizations among children worldwide between 1982 and 2012. Specifically, they undertake a systematic review to identify published research articles on influenza-associated respiratory disease in hospitalized children, and, by aggregating the data from these articles with data collected by hospital-based influenza surveillance, they calculate a pooled estimate of the proportion of children hospitalized with respiratory disease who are positive for influenza. What Did the Researchers Do and Find? Using predefined search criteria, the researchers identified 108 published research articles that provided information on influenza-associated respiratory illness among hospitalized children. In addition, the Global Respiratory Hospitalizations–Influenza Proportion Positive (GRIPP) working group provided 37 hospital-based influenza surveillance datasets. By aggregating the data from these sources using a statistical approach called meta-analysis, the researchers calculated that, overall, influenza was associated with 9.5% of hospitalizations for severe respiratory infection among children under 18 years old worldwide, ranging from 4.8% among children under six months old to 16.4% among children aged 5–17 years. The researchers also calculated that, on average over the study period, influenza resulted in about 374,000 hospitalizations annually among children under one year old (including 228,000 hospitalizations among children less than six months old) and nearly one million hospitalizations annually among children under five years old. Finally, the researchers calculated that influenza-associated hospitalization rates among children under five years old over the study period were more than three times higher in resource-limited countries than in industrialized countries (150 and 48 hospitalizations, respectively, per 100,000 children per year). What Do These Findings Mean? Differences in hospitalization practices, in applications of case definitions, and in influenza testing protocols between settings may affect the accuracy of these findings. Specifically, the approach taken by the researchers may mean that their estimate of the total burden of severe respiratory disease due to influenza is an underestimate of the true situation. Even so, these findings suggest that influenza is an important contributor to hospitalizations for severe respiratory illness among children worldwide. Increasing influenza vaccination coverage among young children and pregnant women could, therefore, reduce the contribution that influenza makes to hospitalizations for respiratory infections among children. Importantly, the estimates of the burden of influenza provided by these findings can now be used by countries considering influenza vaccination programs for children and/or pregnant women to help them investigate the possible health and cost implications of such programs and should also stimulate further research into the development of effective influenza vaccines for young children. Additional Information This list of resources contains links that can be accessed when viewing the PDF on a device or via the online version of the article at http://dx.doi.org/10.1371/journal.pmed.1001977. The UK National Health Service Choices website provides information about respiratory infections, seasonal influenza, influenza vaccination, and influenza vaccination in children The World Health Organization provides information on seasonal influenza (in several languages) and on influenza vaccines The US Centers for Disease Control and Prevention also provides information for patients and health professionals on all aspects seasonal influenza, including information about vaccination, and about children, influenza, and vaccination; its website contains a short video about personal experiences of influenza Flu.gov, a US government website, provides access to information on seasonal influenza and vaccination MedlinePlus has links to further information about influenza and about vaccination (in English and Spanish)

Erratum in - Correction: Temporal Patterns of Influenza A and B in Tropical and Temperate Countries: What Are the Lessons for Influenza Vaccination? PLoS One. 2016 May 2;11(5):e0155089. doi: 10.1371/journal.pone.0155089. Introduction: Determining the optimal time to vaccinate is important for influenza vaccination programmes. Here, we assessed the temporal characteristics of influenza epidemics in the Northern and Southern hemispheres and in the tropics, and discuss their implications for vaccination programmes. Methods: This was a retrospective analysis of surveillance data between 2000 and 2014 from the Global Influenza B Study database. The seasonal peak of influenza was defined as the week with the most reported cases (overall, A, and B) in the season. The duration of seasonal activity was assessed using the maximum proportion of influenza cases during three consecutive months and the minimum number of months with 80% of cases in the season. We also assessed whether co-circulation of A and B virus types affected the duration of influenza epidemics. Results: 212 influenza seasons and 571,907 cases were included from 30 countries. In tropical countries, the seasonal influenza activity lasted longer and the peaks of influenza A and B coincided less frequently than in temperate countries. Temporal characteristics of influenza epidemics were heterogeneous in the tropics, with distinct seasonal epidemics observed only in some countries. Seasons with co-circulation of influenza A and B were longer than influenza A seasons, especially in the tropics. Discussion: Our findings show that influenza seasonality is less well defined in the tropics than in temperate regions. This has important implications for vaccination programmes in these countries. High-quality influenza surveillance systems are needed in the tropics to enable decisions about when to vaccinate. The Global Influenza B Study is supported by an unrestricted research grant from Sanofi Pasteur. info:eu-repo/semantics/publishedVersion

International audience; Introduction: In Africa, the burden of influenza is largely unknown since surveillance schemes exist in very few countries. The National Institute of Hygiene in Morocco implemented a sentinel network for influenza surveillance in 1996. Methodology: Epidemiological and virological surveillances were established and influenza viruses circulating in Morocco were characterised. Four practice-specific indicators were collected during the 1996-1997 season and nasopharyngeal swabs were collected from patients with an influenza-like illness during a three-year period (between 1996 and1998). Laboratory diagnosis was done by viral isolation. The isolates were characterized by hemagglutination- and neuraminidase-inhibition assays and by sequencing the hemagglutinin gene and phylogenetic analysis. Results: Among a total of 673 specimens, 107 (16%) were positive for influenza virus. Seasonal influenza strains were isolated from November to February. Antigenically, A(H1N1), A(H3N2) and B isolates were related to the vaccine strains. Genetically, one 1996/97 isolate A/Rabat/33/96 and the 1997/98 A(H3N2) isolates clustered with the new drift variant A/Sydney/5/97, a vaccine component of the 1998/99 season. Conclusions: These results indicate a seasonal circulation of influenza in Morocco concentrated between November and February. Further, the results demonstrate the importance of including the maximum number of countries in influenza surveillance to contribute to the definition of the influenza vaccine composition.

Item does not contain fulltext BACKGROUND: Data on causes of death due to respiratory illness in Africa are limited. METHODS: From January to April 2013, 28 African countries were invited to participate in a review of severe acute respiratory illness (SARI)-associated deaths identified from influenza surveillance during 2009-2012. RESULTS: Twenty-three countries (82%) responded, 11 (48%) collect mortality data, and 8 provided data. Data were collected from 37 714 SARI cases, and 3091 (8.2%; range by country, 5.1%-25.9%) tested positive for influenza virus. There were 1073 deaths (2.8%; range by country, 0.1%-5.3%) reported, among which influenza virus was detected in 57 (5.3%). Case-fatality proportion (CFP) was higher among countries with systematic death reporting than among those with sporadic reporting. The influenza-associated CFP was 1.8% (57 of 3091), compared with 2.9% (1016 of 34 623) for influenza virus-negative cases (P < .001). Among 834 deaths (77.7%) tested for other respiratory pathogens, rhinovirus (107 [12.8%]), adenovirus (64 [6.0%]), respiratory syncytial virus (60 [5.6%]), and Streptococcus pneumoniae (57 [5.3%]) were most commonly identified. Among 1073 deaths, 402 (37.5%) involved people aged 0-4 years, 462 (43.1%) involved people aged 5-49 years, and 209 (19.5%) involved people aged >/=50 years. CONCLUSIONS: Few African countries systematically collect data on outcomes of people hospitalized with respiratory illness. Stronger surveillance for deaths due to respiratory illness may identify risk groups for targeted vaccine use and other prevention strategies.

International audience; BACKGROUND: In response to the potential threat of an influenza pandemic, several international institutions and governments, in partnership with African countries, invested in the development of epidemiologic and laboratory influenza surveillance capacity in Africa and the African Network of Influenza Surveillance and Epidemiology (ANISE) was formed. METHODS: We used a standardized form to collect information on influenza surveillance system characteristics, the number and percent of influenza-positive patients with influenza-like illness (ILI), or severe acute respiratory infection (SARI) and virologic data from countries participating in ANISE. RESULTS: Between 2006 and 2010, the number of ILI and SARI sites in 15 African countries increased from 21 to 127 and from 2 to 98, respectively. Children 0-4 years accounted for 48% of all ILI and SARI cases of which 22% and 10%, respectively, were positive for influenza. Influenza peaks were generally discernible in North and South Africa. Substantial cocirculation of influenza A and B occurred most years. CONCLUSIONS: Influenza is a major cause of respiratory illness in Africa, especially in children. Further strengthening influenza surveillance, along with conducting special studies on influenza burden, cost of illness, and role of other respiratory pathogens will help detect novel influenza viruses and inform and develop targeted influenza prevention policy decisions in the region.

Following the emergence of 2009 pandemic influenza A virus subtype H1N1 (A[H1N1]pdm09) in the United States and Mexico in April 2009, A(H1N1)pdm09 spread rapidly all over the world. There is a dearth of information about the epidemiology of A(H1N1)pdm09 in Africa, including Morocco. We describe the epidemiologic characteristics of the A(H1N1)pdm09 epidemic in Morocco during 2009-2010, including transmissibility and risk factors associated with fatal disease.We implemented influenza surveillance for patients presenting with influenza-like illness (ILI) at 136 private and public clinics for patients with severe acute respiratory illness (SARI) at 16 regional public hospitals from June 2009 through February 2010. Respiratory samples and structured questionnaires were collected from all enrolled patients, and samples were tested by real-time reverse-transcription polymerase chain reaction for influenza viruses. We estimated the risk factors associated with fatal disease as well as the basic reproduction number (R(0)) and the serial interval of the pandemic virus.From June 2009 through February 2010, we obtained 3937 specimens, of which 1452 tested positive for influenza virus. Of these, 1398 (96%) were A(H1N1)pdm09. Forty percent of specimens from ILI cases (1056 of 2646) and 27% from SARI cases (342 of 1291) were positive for A(H1N1)pdm09. Sixty-four deaths occurred among laboratory-confirmed A(H1N1)pdm09 SARI cases. Among these cases, those who had hypertension (age-adjusted odd ratio [aOR], 28.2; 95% confidence interval [CI], 2.0-398.7), had neurological disorders (aOR, 7.5; 95% CI, 1.5-36.4), or were obese (aOR, 7.1; 95% CI, 1.6-31.1), as well as women of gestational age who were pregnant (aOR, 2.5; 95% CI, 1.1-5.6), were at increased risk of death. Across the country, elevated numbers of locally acquired infections were detected 4 months after the detection of the first laboratory-confirmed case and coincided with the expected influenza season (October-January) in Morocco. We obtained an R(0) estimate of 1.44 (95% CI, 1.32-1.56) and a mean serial interval (±SD) of 2.3 ± 1.4 days (95% CI, 1.6-3.0).Widespread but delayed community transmission of A(H1N1)pdm09 occurred in Morocco in 2009, and A(H1N1)pdm09 became the dominant influenza virus subtype during the 2009-2010 influenza season. The transmissibility characteristics were similar to those observed in other countries.

Vaccination uptake of pregnant women in Morocco during the A (H1N1) pdm09 pandemic was lower than expected. A qualitative study using open-ended questions was developed to explore the main determinants of acceptance and non-acceptance of the monovalent A (H1N1) pdm09 vaccine among pregnant women in Morocco and to identify information sources that influenced their decision-making process. The study sample included 123 vaccinated and unvaccinated pregnant women who were in their second or third trimester between December 2009 and March 2010. They took part in 14 focus group discussions and eight in-depth interviews in the districts of Casablanca and Kenitra. Thematic qualitative analysis identified reasons for vaccine non-acceptance: (1) fear of the monovalent A (H1N1) pdm09 vaccine, (2) belief in an A (H1N1) pdm09 pandemic conspiracy, (3) belief in the inapplicability of the monovalent A (H1N1) pdm09 vaccine to Moroccans, (4) lack of knowledge of the monovalent A (H1N1) pdm09 vaccine, and (5) challenges of vaccination services/logistics. Reasons for vaccine acceptance included: (1) perceived benefits and (2) modeling. Decision-making was strongly influenced by family, community, mass media, religious leaders and health providers suggesting that broad communication efforts should also be used to advocate for vaccination. Meaningful communication for future vaccine campaigns must consider these context-specific findings. As cultural and religious values are shared across many Arab countries, these findings may also provide valuable insights for seasonal influenza vaccine planning in the Middle East and North Africa region at large.

Background There is limited information about the epidemiology of influenza in Africa. We describe the epidemiology and seasonality of influenza in Morocco from 1996 to 2009 with particular emphasis on the 2007–2008 and 2008–2009 influenza seasons. Successes and challenges of the enhanced surveillance system introduced in 2007 are also discussed. Methods Virologic sentinel surveillance for influenza virus was initiated in Morocco in 1996 using a network of private practitioners that collected oro-pharyngeal and naso-pharyngeal swabs from outpatients presenting with influenza-like-illness (ILI). The surveillance network expanded over the years to include inpatients presenting with severe acute respiratory illness (SARI) at hospitals and syndromic surveillance for ILI and acute respiratory infection (ARI). Respiratory samples and structured questionnaires were collected from eligible patients, and samples were tested by immunofluorescence assays and by viral isolation for influenza viruses. Results We obtained a total of 6465 respiratory specimens during 1996 to 2009, of which, 3102 were collected during 2007–2009. Of those, 2249 (72%) were from patients with ILI, and 853 (27%) were from patients with SARI. Among the 3,102 patients, 98 (3%) had laboratory-confirmed influenza, of whom, 85 (87%) had ILI and 13 (13%) had SARI. Among ILI patients, the highest proportion of laboratory-confirmed influenza occurred in children less than 5 years of age (3/169; 2% during 2007–2008 and 23/271; 9% during 2008–2009) and patients 25–59 years of age (8/440; 2% during 2007–2009 and 21/483; 4% during 2008–2009). All SARI patients with influenza were less than 14 years of age. During all surveillance years, influenza virus circulation was seasonal with peak circulation during the winter months of October through April. Conclusion Influenza results in both mild and severe respiratory infections in Morocco, and accounted for a large proportion of all hospitalizations for severe respiratory illness among children 5 years of age and younger.