La grippe saisonnière et ses complications associées peuvent avoir des conséquences de morbimortalité importantes notamment pour les personnes à risque. Les taux de couverture vaccinale (TCV) restent toutefois faibles, dans la plupart des pays européens, et ce malgré l'existence de recommandations vaccinales. À ce jour, peu de travaux permettant d'expliquer ce phénomène ont été réalisés. L'asymétrie d'information entre les groupes cibles, les vaccinateurs et les autorités de santé peut éventuellement expliquer le faible TCV. Outre l'évaluation du fardeau économique de la grippe saisonnière en France, cette thèse explore le processus d'élaboration des recommandations vaccinales et les variables (financières ou non) impactant la propension des médecins généralistes (MGs) à vacciner. Une enquête prospective conduite sur la base des cas de grippe confirmés en laboratoire a estimé l'impact économique de la grippe pour l'assurance maladie à 193 millions d'Euros pour l'année 2010/2011 en France. Les entretiens avec des acteurs clés, impliqués dans l'élaboration des recommandations vaccinales en France et aux Pays-Bas, ont mis en lumière le processus de décision et l'influence notamment des évaluations économiques. L'utilisation systématique d'un classement du niveau de preuve des informations n'a cependant pas été observée, alors qu'elles étaient considérées plutôt comme de faible qualité. Des informations similaires ont été utilisées dans les deux pays ; on observe néanmoins des différences entre les groupes cibles ; le jugement des experts étant crucial pour le processus de décision. Une étude pilote, conduite auprès des MGs en France, a identifié les incitations financières et non-monétaires à vacciner les groupes cibles. Cette étude a permis de mettre en exergue le poids des incitations non-monétaires dans la promotion de la vaccination contre la grippe saisonnière en France : niveau de preuves scientifiques sur l'efficacité du vaccin, transparence des recommandations vaccinales, nouvelles modalités organisationnelles. / Seasonal influenza complications may cause hospitalization and even death. Despite the existence of vaccination recommendations to risk-groups, the vaccination coverage rates (VCR) in most European countries are low. Currently, few studies have been undertaken to explain this phenomenon. Information asymmetry between target groups, vaccinators and health authorities may possibly explain the low VCR. This thesis aimed at investigating (1) the economic burden of seasonal influenza in France, (2) the decision-making process for developing seasonal vaccination recommendations and (3) the incentives that would motivate general practitioners (GPs) to promote vaccination. A prospective survey conducted with laboratory-confirmed cases of influenza has shown the important economic impact of influenza under the perspective of the French Health Insurance. The main cost drivers are hospitalizations and daily allowances. Interviews with key actors, in France and in the Netherlands, involved in the development of vaccination recommendations explored their perceptions about the decision-making process and the influence of economic evaluations and other information on decisions. No systematic grading of the evidence was observed, whereas it was considered of low quality. Similar information was used in both countries, but as experts’ judgement was crucial for the process, differences about the target groups for vaccination were observed. Financial incentives to Dutch vaccinators were associated with their higher VCR. A pilot-study web-surveyed GPs, major vaccinators in France, about the influence of existing financial and non-monetary incentives. GPs were more likely to promote vaccination under non-monetary incentives. Probably because they were generally in favour of vaccinations, including the influenza vaccine; but they seek evidence proving the effectiveness of the vaccine and transparency of vaccination recommendations.

INTRODUÇÃO: A adesão à vacinação contra influenza é historicamente baixa entre profissionais da área da saúde (PAS) (2 a 36%). A ocorrência de sintomas respiratórios após vacinação é freqüentemente interpretada como falha vacinal. No Hospital das Clínicas da FMUSP, um estudo preliminar mostrou que as principais razões para não adesão são a percepção da ineficácia da vacina e o medo de reações adversas. OBJETIVOS: Identificar a incidência de eventos adversos pós-vacinação e identificar os vírus respiratórios (VR) responsáveis por eventuais episódios de infecção de via aérea superior (IVAS) que ocorram entre indivíduos vacinados. MÉTODOS: Foi seguida uma coorte de 398 PAS vacinados objetivando verificar a ocorrência de eventos adversos até 48 h após a vacinação. Durante 4 meses, 337 PAS foram seguidos 2 vezes por semana para avaliar a ocorrência de sintomas respiratórios. Lavados nasais foram coletados na presença de sintomas para pesquisa de VR. A técnica de imunofluorescência direta foi usada para diagnosticar vírus sincicial respiratório, influenza A e B, adenovírus e parainfluenza. PCR foi utilizada para detectar picornavírus e coronavírus e PCR em tempo real para diagnosticar metapneumovírus. Para assegurar melhor sensibilidade, influenza A e B foi também detectado pela PCR em tempo real e adenovírus pela PCR. RESULTADOS: Eventos adversos foram relatados por 30% dos PAS, predominando cefaléia (15,1%), mialgia (14,3%) e mal estar (13,6%). Nenhum evento adverso grave foi observado. Cento e vinte e um PAS (35,9%) desenvolveram sintoma respiratório durante o seguimento e lavado nasal foi colhido em 93 dos 192 episódios apresentados. Vírus influenza A foi detectado em 5 dos 93 episódios (5,3%) e outros vírus respiratórios em 26 (27,9%). No restante dos 61 episódios (65,6%) nenhum vírus foi encontrado. A densidade de incidência de infecção pelo vírus influenza foi de 4,3 episódios por 100 pacientes-mês enquanto que a densidade de infecção por outros vírus respiratórios foi de 10,8 episódios por pacientes-mês. CONCLUSÃO: Vacina da influenza é segura. O medo de eventos adversos grave parece injustificado, bem como, a percepção da ineficácia da vacina. O presente estudo evidencia que IVAS após vacinação é predominantemente causada por outros vírus respiratórios (28%) e não pelo vírus influenza (5%) / INTRODUCTION: Compliance with influenza vaccination has been historically poor among health care workers (HCW), ranging from 2 to 36% world around. The occurrence of respiratory symptoms following influenza vaccination is frequently taken as vaccine failure which reinforces vaccine disbelief. A preliminary study conducted at Hospital das Clínicas, University of São Paulo School of Medical Sciences, showed that the main reasons for non-compliance with influenza vaccination were the perception of vaccine inefficacy and fear of adverse events. OBJECTIVES: To determine the incidence of adverse events after seasonal influenza vaccination and identify other respiratory viruses causing upper respiratory infections in vaccinated HCWs. METHODS: A cohort of 398 vaccinated HCWs was prospectively surveyed for the occurrence of any adverse event in the first 48h after vaccination. A subset of the original cohort (337 HCWs) was followed up during four months, twice a week, for the detection of respiratory symptoms. Nasal washes were taken if respiratory symptoms occurred. Direct immunofluorescent assay (DFA) was performed for the detection of respiratory syncytial virus (RSV), influenza (INF) A and B, parainfluenza (PIV) 1, 2 and 3, and adenovirus (ADV). PCR was performed for the detection of human rhinoviruses (HRV), ADV and coronaviruses (hCoV); and real time PCR for the detection of human metapneumovirus (hMPV). To assure greatest sensitivity of influenza diagnosis, real time PCR was added to the diagnostic tools of influenza viruses. RESULTS: Adverse events were reported by 30% of the HCWs, being headache and myalgia reported by 50% and 47% of the participants, respectively. No severe adverse event was observed. One hundred and twenty-one HCWs (35.9%) developed 192 episodes of respiratory symptoms during follow-up and nasal washes were taken in 93 of them. Influenza A virus was detected in five of the 93 episodes (5.3%) and other respiratory viruses in 26 (27.9%). In the remaining 61 episodes (65.6%) no respiratory virus was identified. The incidence density of influenza was 4.3 episodes per 100 HCW-month, while the incidence density of other respiratory viruses was 10.8 episodes per HCW-month. CONCLUSIONS: Influenza vaccine is safe. The fear of adverse events as well as the perception of vaccine inefficacy seems to be unjustified in this population. The present study showed that the occurrence of upper respiratory infection during the four months following seasonal influenza vaccination of HCWs is generally caused by other respiratory viruses (28%) and not by influenza viruses (5%)

INTRODUÇÃO: A adesão à vacinação contra influenza é historicamente baixa entre profissionais da área da saúde (PAS) (2 a 36%). A ocorrência de sintomas respiratórios após vacinação é freqüentemente interpretada como falha vacinal. No Hospital das Clínicas da FMUSP, um estudo preliminar mostrou que as principais razões para não adesão são a percepção da ineficácia da vacina e o medo de reações adversas. OBJETIVOS: Identificar a incidência de eventos adversos pós-vacinação e identificar os vírus respiratórios (VR) responsáveis por eventuais episódios de infecção de via aérea superior (IVAS) que ocorram entre indivíduos vacinados. MÉTODOS: Foi seguida uma coorte de 398 PAS vacinados objetivando verificar a ocorrência de eventos adversos até 48 h após a vacinação. Durante 4 meses, 337 PAS foram seguidos 2 vezes por semana para avaliar a ocorrência de sintomas respiratórios. Lavados nasais foram coletados na presença de sintomas para pesquisa de VR. A técnica de imunofluorescência direta foi usada para diagnosticar vírus sincicial respiratório, influenza A e B, adenovírus e parainfluenza. PCR foi utilizada para detectar picornavírus e coronavírus e PCR em tempo real para diagnosticar metapneumovírus. Para assegurar melhor sensibilidade, influenza A e B foi também detectado pela PCR em tempo real e adenovírus pela PCR. RESULTADOS: Eventos adversos foram relatados por 30% dos PAS, predominando cefaléia (15,1%), mialgia (14,3%) e mal estar (13,6%). Nenhum evento adverso grave foi observado. Cento e vinte e um PAS (35,9%) desenvolveram sintoma respiratório durante o seguimento e lavado nasal foi colhido em 93 dos 192 episódios apresentados. Vírus influenza A foi detectado em 5 dos 93 episódios (5,3%) e outros vírus respiratórios em 26 (27,9%). No restante dos 61 episódios (65,6%) nenhum vírus foi encontrado. A densidade de incidência de infecção pelo vírus influenza foi de 4,3 episódios por 100 pacientes-mês enquanto que a densidade de infecção por outros vírus respiratórios foi de 10,8 episódios por pacientes-mês. CONCLUSÃO: Vacina da influenza é segura. O medo de eventos adversos grave parece injustificado, bem como, a percepção da ineficácia da vacina. O presente estudo evidencia que IVAS após vacinação é predominantemente causada por outros vírus respiratórios (28%) e não pelo vírus influenza (5%) / INTRODUCTION: Compliance with influenza vaccination has been historically poor among health care workers (HCW), ranging from 2 to 36% world around. The occurrence of respiratory symptoms following influenza vaccination is frequently taken as vaccine failure which reinforces vaccine disbelief. A preliminary study conducted at Hospital das Clínicas, University of São Paulo School of Medical Sciences, showed that the main reasons for non-compliance with influenza vaccination were the perception of vaccine inefficacy and fear of adverse events. OBJECTIVES: To determine the incidence of adverse events after seasonal influenza vaccination and identify other respiratory viruses causing upper respiratory infections in vaccinated HCWs. METHODS: A cohort of 398 vaccinated HCWs was prospectively surveyed for the occurrence of any adverse event in the first 48h after vaccination. A subset of the original cohort (337 HCWs) was followed up during four months, twice a week, for the detection of respiratory symptoms. Nasal washes were taken if respiratory symptoms occurred. Direct immunofluorescent assay (DFA) was performed for the detection of respiratory syncytial virus (RSV), influenza (INF) A and B, parainfluenza (PIV) 1, 2 and 3, and adenovirus (ADV). PCR was performed for the detection of human rhinoviruses (HRV), ADV and coronaviruses (hCoV); and real time PCR for the detection of human metapneumovirus (hMPV). To assure greatest sensitivity of influenza diagnosis, real time PCR was added to the diagnostic tools of influenza viruses. RESULTS: Adverse events were reported by 30% of the HCWs, being headache and myalgia reported by 50% and 47% of the participants, respectively. No severe adverse event was observed. One hundred and twenty-one HCWs (35.9%) developed 192 episodes of respiratory symptoms during follow-up and nasal washes were taken in 93 of them. Influenza A virus was detected in five of the 93 episodes (5.3%) and other respiratory viruses in 26 (27.9%). In the remaining 61 episodes (65.6%) no respiratory virus was identified. The incidence density of influenza was 4.3 episodes per 100 HCW-month, while the incidence density of other respiratory viruses was 10.8 episodes per HCW-month. CONCLUSIONS: Influenza vaccine is safe. The fear of adverse events as well as the perception of vaccine inefficacy seems to be unjustified in this population. The present study showed that the occurrence of upper respiratory infection during the four months following seasonal influenza vaccination of HCWs is generally caused by other respiratory viruses (28%) and not by influenza viruses (5%)