Hervé Kadjo

Influenza Surveillance in 15 Countries in Africa, 2006-2010

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.

Epidemiological and virological characteristics of influenza B: results of the Global Influenza B Study

Literature on influenza focuses on influenza A, despite influenza B having a large public health impact. The Global Influenza B Study aims to collect information on global epidemiology and burden of disease of influenza B since 2000.

Temporal patterns of influenza A and B in tropical and temperate countries : what are the lessons for influenza vaccination?

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.

Global epidemiology of non-influenza RNA respiratory viruses: data gaps and a growing need for surveillance

Summary Together with influenza, the non-influenza RNA respiratory viruses (NIRVs), which include respiratory syncytial virus, parainfluenza viruses, coronavirus, rhinovirus, and human metapneumovirus, represent a considerable global health burden, as recognised by WHOs Battle against Respiratory Viruses initiative. By contrast with influenza viruses, little is known about the contemporaneous global diversity of these viruses, and the relevance of such for development of pharmaceutical interventions. Although far less advanced than for influenza, antiviral drugs and vaccines are in different stages of development for several of these viruses, but no interventions have been licensed. This scarcity of global genetic data represents a substantial knowledge gap and impediment to the eventual licensing of new antiviral drugs and vaccines for NIRVs. Enhanced genetic surveillance will assist and boost research and development into new antiviral drugs and vaccines for these viruses. Additionally, understanding the global diversity of respiratory viruses is also part of emerging disease preparedness, because non-human coronaviruses and paramyxoviruses have been listed as priority concerns in a recent WHO research and development blueprint initiative for emerging infectious diseases. In this Personal View, we explain further the rationale for expanding the genetic database of NIRVs and emphasise the need for greater investment in this area of research.

Multiyear Persistence of 2 Pandemic A/H1N1 Influenza Virus Lineages in West Africa

ABSTRACT Our understanding of the global ecology of influenza viruses is impeded by historically low levels of viral surveillance in Africa. Increased genetic sequencing of African A/H1N1 pandemic influenza viruses during 2009–2013 revealed multiyear persistence of 2 viral lineages within West Africa, raising questions about the roles of reduced air traffic and the asynchrony of seasonal influenza epidemics among West African countries in the evolution of independent lineages. The potential for novel influenza virus lineages to evolve within Africa warrants intensified influenza surveillance in Africa and other understudied areas.

Sentinel surveillance for influenza and other respiratory viruses in Côte d’Ivoire, 2003–2010

Background  Many countries in Africa have lacked sentinel surveillance systems for influenza and are under‐represented in data used for global vaccine strain selection.

Vulnerable Groups Within a Vulnerable Population: Awareness of the A(H1N1)pdm09 Pandemic and Willingness to Be Vaccinated Among Pregnant Women in Ivory Coast

BACKGROUND Because little is known about attitudes toward influenza and influenza vaccine among pregnant women in West Africa, before local distribution of A(H1N1)pdm09 vaccine in Ivory Coast we assessed knowledge of the pandemic and acceptance of the A(H1N1)pdm09 vaccine in a diverse population of pregnant women. METHODS A cross-sectional intercept survey of 411 pregnant women in 4 prenatal care settings was conducted during 15-28 February 2010 in Abidjan, Ivory Coast. RESULTS The majority (64.5%) of pregnant women said they had heard of the influenza pandemic, and of these, the majority (61.3%) were aware of the A(H1N1)pdm09 vaccine. However, awareness varied significantly by clinical setting, education level, and access to media (P < .001 for all comparisons). After adjustment for other sociodemographic factors, college-educated women were 16.8 (95% confidence interval [CI], 3.3-85.2) times as likely as women without formal education to be aware of the pandemic. After controlling for both education and demographic characteristics, women with televisions were 5 times as likely as women without television to be aware of the pandemic (adjusted odds ratio [aOR], 4.94; 95% CI, 1.34-18.17). Of those aware of the influenza pandemic, 69.8% said they would accept the A(H1N1)pdm09 vaccine while they were pregnant. Although awareness was highest in private prenatal care clinics, compared with public outpatient clinics (90.6% vs 37.5%), acceptance of vaccine was significantly lower in private settings, compared with public outpatient settings (57.3% vs 87.2%; P < .001 for each comparison). CONCLUSIONS Gaps in knowledge about the influenza pandemic and vaccine highlight the challenges of pandemic preparedness in poorer countries, where substantial disparities in education and media access are evident.

Epidemiology of rubella infection and genotyping of rubella virus in Cote d’Ivoire, 2012-2016: KADJO et al.

Rubella is a contagious disease caused by the rubella virus (RuV) that can lead to serious birth defects when women are infected in early pregnancy. This study aimed to describe the epidemiology and genetic diversity of rubella viruses in Cote d’Ivoire (CIV). Blood or oral fluid samples collected from suspected measles cases were first tested for the presence of measles specific IgM antibodies by enzyme‐linked immunosorbent assay (ELISA). All measles IgM negative or indeterminate samples were tested for rubella IgM antibody using ELISA. Rubella‐IgM–positive samples were tested by real‐time reverse transcription polymerase chain reaction (RT‐PCR) for the presence of rubella virus RNA. Real‐time RT‐PCR–positive RNA samples were used as template to amplify the 739 nt region used for rubella genotyping. PCR‐positive samples were sequenced and phylogenetic analysis performed. Between 2012 and 2016, 4121 serums and 126 oral fluids were collected through the measles surveillance system. Of these, 3823 and 108 respectively were measles IgM negative or indeterminate. Subsequent testing for rubella found that 690 of 3823 (18%) serum samples and 25 of 108 (23%) oral fluid samples were rubella IgM‐positive. The 739 nt segment of the E1 glycoprotein gene was amplified and sequenced for two serums and seven oral fluids samples. Phylogenetic analysis showed that the rubella viruses from CIV belonged to genotypes 1G (eight samples) and 2B (one sample). Rubella virus genotype 2B was found in CIV for the first time. These data contribute to baseline information on rubella virus strains found in CIV before the introduction of rubella vaccine.

Distribution of influenza virus types by age using case-based global surveillance data from twenty-nine countries, 1999-2014

BackgroundInfluenza 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).MethodsFor 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.ResultsThe 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.ConclusionsThese results highlight the importance of presenting burden of disease estimates by age group and virus (sub)type.

DETECTION OF NON-INFLUENZA VIRUSES IN ACUTE RESPIRATORY INFECTIONS IN CHILDREN UNDER FIVE-YEAR-OLD IN COTE D’IVOIRE (JANUARY – DECEMBER 2013)

Background: Influenza sentinel surveillance in Cote d’Ivoire showed that 70% of Acute Respiratory Infections (ARI) cases remained without etiology. This work aims to describe the epidemiological, clinical, and virological pattern of ARI that tested negative for influenza virus, in children under five years old. Materials and Methods: one thousand and fifty nine samples of patients presenting influenza Like Illness (ILI) or Severe Acute Respiratory Infections (SARI) symptoms were tested for other respiratory viruses using multiplex RT-PCR assays targeting 10 respiratory viruses. Results: The following pathogens were detected as follows, hRV 31,92% (98/307), hRSV 24.4% (75/329), PIV 20.5% (63/307), HCoV 229E 12,05% (37/307), hMPV 6.2% (19/307), HCoVOC43 1.0% (3/307) and EnV 1.0% (3/307). Among the 1,059 specimens analyzed, 917 (86.6%) were ILI samples and 142 (23.4%) were SARI samples. The proportion of children infected with at least one virus was 29.8% (273/917) in ILI cases and 23.9% (34/142) in SARI cases. The most prevalent viruses, responsible for ILI cases were hRV with 35.89% (98/273) and hRSV in SARI cases with 41.2% (14/34) of cases. Among the 1,059 patients, only 22 (2.1%) children presented risk factors related to the severity of influenza virus infection. Conclusion: This study showed that respiratory viruses play an important role in the etiology of ARI in children. For a better understanding of the epidemiology of ARI and improved case management, it would be interesting in this context to expand the surveillance of influenza to other respiratory viruses.