Integrative study of pandemic A/H1N1 influenza infections: design and methods of the CoPanFlu-France cohort.

BACKGROUND: The risk of influenza infection depends on biological characteristics, individual or collective behaviors and the environmental context. The Cohorts for Pandemic Influenza (CoPanFlu) France study was set up in 2009 after the identification of the novel swine-origin A/H1N1 pandemic influenza virus. This cohort of 601 households (1450 subjects) representative for the general population aims at using an integrative approach to study the risk and characteristics of influenza infection as a complex combination of data collected from questionnaires regarding sociodemographic, medical, behavioral characteristics of subjects and indoor environment, using biological samples or environmental databases. METHODS/DESIGN: Households were included between December 2009 and July 2010. The design of this study relies on systematic follow-up visits between influenza seasons and additional visits during influenza seasons, when an influenza-like illness is detected in a household via an active surveillance system. During systematic visits, a nurse collects individual and environmental data on questionnaires and obtains blood samples from all members of the household. When an influenza-like-illness is detected, a nurse visits the household three times during the 12 following days, and collects data on questionnaires regarding exposure and symptoms, and biological samples (including nasal swabs) from all subjects in the household. The end of the follow-up period is expected in fall 2012. DISCUSSION: The large amount of data collected throughout the follow-up will permit a multidisciplinary study of influenza infections. Additional data is being collected and analyzed in this ongoing cohort. The longitudinal analysis of these households will permit integrative analyses of complex phenomena such as individual, collective and environmental risk factors of infection, routes of transmission, or determinants of the immune response to infection or vaccination.

The public's preventive strategies in response to the pandemic influenza A/H1N1 in France: distribution and determinants.

OBJECTIVES: Since the emergence of the pandemic influenza A/H1N1, people were encouraged to adopt a large range of pharmaceutical and non-pharmaceutical measures in order to counter the risk of infection. The aim of this article is to identify and to explain the different types of preventive strategies adopted by the French population. METHODS: The data are based on a phone survey conducted with a representative sample of the French population (N=1003) in December 2009 (cooperation rate=45.9%). Logistic regressions were used in order to characterize the different preventive behavioral patterns towards the A/H1N1 influenza. RESULTS: Four types of behavioral strategies have been identified: 31.5% of the respondents combined vaccination (intention or action, regardless of the nature of the vaccine) with non-pharmaceutical measures, 8.8% wanted to get exclusively vaccinated, 42.0% took non-pharmaceutical steps only and 17.7% didn't protect themselves at all. Significant social and cognitive variables were found to predict membership of each group. CONCLUSIONS: These results indicate that a large majority of that is mainly population adopted a selective strategy rather than a cumulative one as it was recommended, a choice mostly explained by the level of risk perception.

Factors in vaccination intention against the pandemic influenza A/H1N1.

BACKGROUND: Vaccination against pandemic influenza A/H1N1 is an effective strategy to mitigate the spread of the disease. While the vaccine is now available, social acceptance remains relatively uncertain in many societies. The purpose of this study was to examine the beliefs, attitudes and practices associated with the intention to get vaccinated against the A/H1N1 virus among the general population in France. METHODS: A representative sample of 1001 individuals (stratified random recruitment procedure, ages 16-90 years) was interviewed by telephone. The questionnaire included a variety of items associated with socio-demographic characteristics, risk perceptions, illness perceptions, political attitudes and worldviews as well as intention to get vaccinated. RESULTS: More than 6 out of 10 of the respondents indicated that they planned to get vaccinated when the vaccine becomes available. The same proportion of parents also reported the intention to vaccinate their children against the disease. In multiple regression analyses, socio-cognitive factors consistently predicting influenza A/H1N1 vaccination were: level of worry, risk perception and previous experience of vaccine against seasonal flu. CONCLUSIONS: The factors found to predict vaccination intention and their distribution are assumed to be a consequence of the fact that people perceive the risk of swine flu to be similar to that of seasonal flu. As a result, in the absence of an increase of the risk perception of pandemic influenza A/H1N1, a very low level of actual vaccination is forecasted. Behavioural change would require that the risks and consequences of pandemic influenza A/H1N1 be perceived as highly different from seasonal flu.

Lay perceptions of the pandemic influenza threat.

A national survey on the public perception of the pandemic threat was conducted in France during the summer of 2008. Although the majority of the respondents displayed beliefs and attitudes toward the pandemic threat that could be considered as adaptive in the face of an outbreak, our results suggest that there are identifiable needs for public information about the transmission and prevention of the disease.

The role of environmental and individual factors in the social epidemiology of chikungunya disease on Mayotte Island.

This article examines the role of environmental and individual factors in the social epidemiology of chikungunya disease on the island of Mayotte (South-western Indian Ocean). In an epidemic setting, an interdisciplinary study combining interviews, observations, and serological tests was conducted to: (1) estimate the frequency and social distribution of chikungunya disease and (2) identify its principal cognitive, behavioral, and environmental determinants within a stratified random sample of the Mayotte population (n=888). Semi-parametric tests and multiple correspondence analyses were used to describe the statistical relationships between the different classes of variables examined in this study and the presence of antibodies attributable to chikungunya. These analyses highlighted differences between two main types of populations: one more autochthonous, more urban and better educated population, which shared 'legitimate' representations of the disease-from a biomedical viewpoint; and the other more migrant, more suburban, and more deprived, which is characterized by folk theories of chikungunya virus infection. Moreover, a series of logistic regression models revealed that social disparities in the distribution of virus infection were primarily structured by the housing conditions and cognitive representations of the disease held by the participants. These results suggest that environmental and individual factors are equally crucial in epidemic settings, and that they could explain, to a considerable extent, the social differences observed in morbidity associated with recent emerging infectious diseases in tropical countries.

[French School of Public Health (FSPH). II. Risk analysis and regulation]. / L'Ecole des Hautes Etudes en Santé Publique (EHESP). II. L'analyse et la regulation du risque.

The project of a center for risk analysis and regulation is founded paradoxical statement: although health risks and crisis are major a focus of society and a driving force for institutional change and regulations, France, contrary to many industrialized countries, has no multidisciplinary center in this field. This is likely due to the weakness of French risk research, resulting in few international publications and little visibility. The creation of the French School of Public Health (FSPH) brings an opportunity to fill this gap by gathering together, in the same center, researchers and teachers specializing in risk assessment and management--the conceptual basis of public health. The main objectives of this risk center, which will link the scientific knowledge on health with the public decision-making process, are--to organize a network of researchers with expertise in risk analysis and regulation;--to bolster the presence of French risk research on the international stage;--to increase international publication and to share experiences and methodological innovations with other countries ; and 4) to organize integrated training on health risks. Through the development of analyses on risk evaluation and regulation, this center will contribute to the promotion of public health.

[Chikungunya, La Réunion and Mayotte, 2005-2006: an epidemic without a story?]. / Chikungunya, La Réunion et Mayotte, 2005-2006: une epidémie sans histoire?

Many triggering factors for onset of emerging infectious diseases are now recognised, such as: globalisation, demographic increase, population movements, international trade, urbanisation, forest destruction, climate changes, loss in biodiversity, and extreme life conditions such as poverty, famine and war. Epidemic burden is often leading to disasters, in terms of human losses, as well as economic, political or social consequences. These outbreaks may jeopardize within a few weeks or months, industry, trade, or tourism. While dengue and its most severe forms (hemorrhagic and shock syndrome) is spreading all over the tropical world, another arbovirosis, chikungunya disease dramatically spread in Indian Ocean islands where 30 to 75% of population were infected in 2005 and 2006, and then extended its progression towards India, Sri Lanka, Indonesia, Malaysia, Maldives islands with more than a million people infected with the East-African strain, replacing the former Asian strain which was known to prevail more than 30 years ago in India. Patients experience sequelae with disability, work loss, and rarely severe outcome recently identified in La Réunion and Mayotte (French overseas territories). No country, no part of the world may consider itself as protected against such events. However, consequences of emerging or re-emerging diseases are more and more unacceptable when they impact the poorest countries of the world. Viruses, bacteria, as well as wild animals, birds, or arthropods are not stopped by borders. It is time now to promote barriers against infectious diseases, including prevention, anticipation, disease surveillance and research. This is not only for humanitarian reasons, but also for contributing to a sustainable development with equity for worldwide population. This report presents comprehensive actions taken in 2006 for tracing the epidemic and mobilise research, as requested to the task force set up by the Prime Minister by March 20, 2006.

[How to apply the 4th March 2002 French law, making information to patients mandatory after the identification of a new risk?]. / Comment appliquer la loi sur l'information des patients en cas de risque nouveau identifié?

The 4th March 2002 French law, through its L. 1111-2 article, makes it mandatory to inform persons who received medical care, investigation or preventive intervention when a new risk is identified after the act was done. The article L. 1413-13 of the law adds that health authorities can summon responsible professionals if they establish a lack of information, unless it is impossible to find again exposed patients. The text relates conclusions of the working group set up in 2003 by the Chief Medical Officer whose mission was to identify what kind of situations fitted this new right and the consequences, in terms of action, of the qualification of an event as a "new risk". The two main outcomes were to clear up the basic ambiguity concerning the term of "new risk" and to propose a framework defining the multiple stages by which it has to be assessed. Furthermore, the diversity of potential situations to be faced in connection with the possible consequences of information raised the issue of objectives aimed by the lawmaker. Despite good intentions, the law as laid down appears insufficient to ensure that this new right will be always beneficial to the patients, in terms of public health.

Causal analysis of H1N1pdm09 influenza infection risk in a household cohort.

BACKGROUND: Obtaining a comprehensive quantitative figure of the determinants of influenza infection will help identify priority targets for future influenza mitigation interventions. We developed an original causal model integrating highly diverse factors and their dependencies, to identify the most critical determinants of pandemic influenza infection (H1N1pdm09) during the 2010-2011 influenza season. METHODS: We used data from 601 households (1450 participants) included in a dedicated cohort. Structural equations were used to model direct and indirect relationships between infection and risk perception, compliance with preventive behaviours, social contacts, indoor and outdoor environment, sociodemographic factors and pre-epidemic host susceptibility. Standardised estimates (ßstd) were used to assess the strength of associations (ranging from -1 for a completely negative association to 1 for a completely positive association). RESULTS: Host susceptibility to H1N1pdm09 and compliance with preventive behaviours were the only two factors directly associated with the infection risk (ßstd=0.31 and ßstd=-0.21). Compliance with preventive behaviours was influenced by risk perception and preventive measures perception (ßstd=0.14 and ßstd=0.27). The number and duration of social contacts were not associated with H1N1pdm09 infection. CONCLUSIONS: Our findings suggest that influenza vaccination in addition to public health communication campaigns focusing on personal preventive measures should be prioritised as potentially efficient interventions to mitigate influenza epidemics.

Healthcare worker compliance with seasonal and pandemic influenza vaccination.

Healthcare workers (HCWs) can be an important source of transmission of influenza to patients and family members, and their well-being is fundamental to the maintenance of healthcare services during influenza outbreaks and pandemics. Unfortunately, studies have shown consistently low levels of compliance with influenza vaccination among HCWs, a finding that became particularly pronounced during recent pandemic vaccination campaigns. Among the variables associated with vaccine acceptance in this group are demographic factors, fears and concerns over vaccine safety and efficacy, perceptions of risk and personal vulnerability, past vaccination behaviours and experience with influenza illness, as well as certain situational and organisational constructs. We report the findings of a review of the literature on these factors and highlight some important challenges in interpreting the data. In particular, we point out the need for longitudinal study designs, as well as focused research and interventions that are adapted to the most resistant HCW groups. Multi-pronged strategies are an important step forward in ensuring that future influenza vaccination campaigns, whether directed at seasonal or pandemic strains, will be successful in ensuring broad coverage among HCWs.

Factors associated with post-seasonal serological titer and risk factors for infection with the pandemic A/H1N1 virus in the French general population.

The CoPanFlu-France cohort of households was set up in 2009 to study the risk factors for infection by the pandemic influenza virus (H1N1pdm) in the French general population. The authors developed an integrative data-driven approach to identify individual, collective and environmental factors associated with the post-seasonal serological H1N1pdm geometric mean titer, and derived a nested case-control analysis to identify risk factors for infection during the first season. This analysis included 1377 subjects (601 households). The GMT for the general population was 47.1 (95% confidence interval (CI): 45.1, 49.2). According to a multivariable analysis, pandemic vaccination, seasonal vaccination in 2009, recent history of influenza-like illness, asthma, chronic obstructive pulmonary disease, social contacts at school and use of public transports by the local population were associated with a higher GMT, whereas history of smoking was associated with a lower GMT. Additionally, young age at inclusion and risk perception of exposure to the virus at work were identified as possible risk factors, whereas presence of an air humidifier in the living room was a possible protective factor. These findings will be interpreted in light of the longitudinal analyses of this ongoing cohort.

Predicting the lay preventive strategies in response to avian influenza from perceptions of the threat.

BACKGROUND: The identification of patterns of behaviors that lay people would engage in to protect themselves from the risk of infection in the case of avian influenza outbreak, as well as the lay perceptions of the threat that underlie these risk reduction strategies. METHODOLOGY/PRINCIPAL FINDINGS: A population-based survey (N = 1003) was conducted in 2008 to understand and describe how the French public might respond to a possible outbreak. Factor analyses highlighted three main categories of risk reduction strategies consisting of food quality assurance, food avoidance, and animal avoidance. In combination with the fear of contracting avian influenza, mental representations associated with the manifestation and/or transmission of the disease were found to significantly and systematically shape the behavioral responses to the perceived threat. CONCLUSIONS/SIGNIFICANCE: This survey provides insight into the nature and predictors of the protective patterns that might be expected from the general public during a novel domestic outbreak of avian influenza.

Modelers' perception of mathematical modeling in epidemiology: a web-based survey.

BACKGROUND: Mathematical modeling in epidemiology (MME) is being used increasingly. However, there are many uncertainties in terms of definitions, uses and quality features of MME. METHODOLOGY/PRINCIPAL FINDINGS: To delineate the current status of these models, a 10-item questionnaire on MME was devised. Proposed via an anonymous internet-based survey, the questionnaire was completed by 189 scientists who had published in the domain of MME. A small minority (18%) of respondents claimed to have in mind a concise definition of MME. Some techniques were identified by the researchers as characterizing MME (e.g. Markov models), while others-at the same level of sophistication in terms of mathematics-were not (e.g. Cox regression). The researchers' opinions were also contrasted about the potential applications of MME, perceived as highly relevant for providing insight into complex mechanisms and less relevant for identifying causal factors. The quality criteria were those of good science and were not related to the size and the nature of the public health problems addressed. CONCLUSIONS/SIGNIFICANCE: This study shows that perceptions on the nature, uses and quality criteria of MME are contrasted, even among the very community of published authors in this domain. Nevertheless, MME is an emerging discipline in epidemiology and this study underlines that it is associated with specific areas of application and methods. The development of this discipline is likely to deserve a framework providing recommendations and guidance at various steps of the studies, from design to report.

The 2009 pandemic H1N1 influenza vaccination in France: who accepted to receive the vaccine and why?

INTRODUCTION: Previous studies investigating determinants of 2009 (H1N1) pandemic influenza vaccine acceptance have focused on target groups such as healthcare workers. Few studies in the European Union have examined the self-reported reasons as well as predictive socio-demographic and health factors for pandemic influenza vaccine acceptance in the general population, even though influenza vaccine was recommended for all people. METHODS: A nationwide telephone survey was conducted in France during the peak of the outbreak that occurred in December 2009 in adults (≥ 16 years), using a proportional random-digit dialing. RESULTS: Interviews were completed by 1003 individuals, of whom 275 (27.4%) either had received pandemic influenza vaccine during the last weeks or intended to get vaccinated in the next weeks. Acceptance rates of pandemic vaccine were significantly higher among men, more educated and wealthier people, as well as persons who had a prior experience of influenza vaccination. The patterns of self-reported reasons for vaccine acceptance could be broadly divided into 3 groups related to (1) the mental representation of the threat - in particular the beliefs associated with the severity and personal vulnerability to the illness, (2) the perception of efficacy and safety of the vaccine, and (3) trust/distrust toward those advocating the vaccine. CONCLUSIONS: This national study indicates that social and cognitive determinants of pandemic influenza vaccine acceptance among French adults were relatively similar to those identified by previous studies of acceptance of seasonal influenza vaccine.

Risk perception of the "mad cow disease" in France: determinants and consequences.

Since 1996, when bovine spongiform encephalopathy (BSE) was assessed as a possible human transmissible disease, a variant of Creutzfeldt-Jakob disease (vCJD), French people have entered into a long period of fear and avoidance of beef and bovine byproducts, which produced an unprecedented collapse in the beef market. This article deals with the perceived risk of the "mad cow disease" (MCD) in the French general population. Two surveys were conducted on a representative sample of the adult population, the first one in 2000 during the peak of the crisis and the second one 13 months later in a quieter period. The main assumption we made was that changes in beef consumption are strongly related to the perceived risk of MCD, which we defined as people's cognitive and affective responses to hazard. Our objective was to identify the determinants and consequences of this perceived risk and to compare them in different sociopolitical contexts. The results issued from a bivariate and multivariate analysis show that: (i) the distribution of most of the variables significantly related to the perceived risk identified in the first survey had changed in the second survey, in relation with the reduction of worry and the resumption of national beef consumption; (ii) the propensity for self-protection through avoiding or ceasing beef eating was more related to feelings of worry than to subjective vCJD risk assessments; and (iii) the main determinant of less avoidance to beef products was the preference for beef, a feeling identified prior to emergence of the risk of MCD, remaining unchanged in various contexts.

Could measuring of perceived risk among general practitioners have helped anticipate the French BSE crisis?

In October of 2000, a second BSE crisis caught French public authorities unprepared and caused a collapse in beef consumption as well as considerable political turmoil. Data collected between May and July, 2000, among a group of general practitioners (GPs), while national consumption of beef was back to pre-BSE levels, paradoxically showed high latent risk perception, suggesting a new crisis was possible or likely.