Thierry Blanchon

Virtual surveillance of communicable diseases: a 20-year experience in France

Inserm has developed, since 1984, an information system based on a computer network of physicians in France. It allows for constitution of large databases on diseases, with individual description of cases, and to explore some aspects of the mathematical theory of communicable diseases. We developed user-friendly interfaces for remote data entry and GIS tools providing real-time atlas of the epidemiologic situation in any location. The continuous and ongoing surveillance network is constituted of about 1200 sentinel voluntary and unpaid investigators. We studied their motivation, reasons for either withdrawal or compliance using survival analyses. We implemented early warning systems for outbreak detection and for time-space forecasting. We conducted epidemiological surveys for investigating outbreaks. Large available time and space series allowed us to calibrate and explore synchronism of influenza epidemics, to test the assumption of panmixing in susceptibles-infectious-removed type models and to study the role of closing school in influenza morbidity and mortality in elderly. More than 250 000 cases of influenza, 150 000 cases of acute diarrheas, 35 000 patients for whom HIV tests have been prescribed by general practitioners and 25 000 cases of chickenpox have been collected. Detection of regional influenza or acute diarrhea outbreaks and forecasting of epidemic trends three weeks ahead are currently broadcasted to the French media and published on Sentiweb© on a weekly basis. Age-cohort-period models assessed field effectiveness of mass immunization strategies against measles and influenza in the country. Case-control studies with more than 1200 sets of cases of acute diarrheas and their matched controls showed the role of calicivirus and rotavirus as probable major causes of gastroenteritis during recurrent widespread outbreaks in winter in France. An age-specific model for chickenpox showed the probable role of children in disease transmission to their susceptible parents or grandparents. High level of synchronism between influenza epidemics has been demonstrated, either at a regional level (in France) or between France and the USA. The designation of our lab as a WHO collaborating center for electronic disease surveillance stimulates the development of global monitoring of diseases. We developed operational systems that are now available for the global monitoring of influenza (FluNet©), and human and animal rabies (RABNET©). Extension of electronic syndromic surveillance is needed in the world for improving surveillance capacities and real-time response against emerging diseases.

Urinary Incontinence in French Women: Prevalence, Risk Factors, and Impact on Quality of Life

BACKGROUND The lack of epidemiologic data on the prevalence of female urinary incontinence (UI) attending general practitioners (GPs) in France led us to conduct a cross-sectional study in our country. OBJECTIVES To determine the prevalence of UI and to assess its impact on the quality of life (QoL). DESIGN, SETTING, AND PARTICIPANTS This cross-sectional study of women aged >18 yr was conducted by attending GPs between June 2007 and July 2007. MEASUREMENTS The main outcome measures were urinary symptoms, functional impairment, International Consultation on Incontinence Questionnaire-Short Form score, and medical care seeking. RESULTS AND LIMITATIONS Overall, 241 GPs enrolled 2183 women seen during 1 d. The prevalence of UI was 26.8% (n=584) and increased with age, body mass index (BMI), and number of children delivered (p<0.0001). Among women with UI, 496 were included in a cross-sectional survey: 45.2% (n=224) had stress UI, 42.1% (n=209) had mixed UI, and 10.9% (n=53) had urge UI, while 2% (n=10) had UI of indeterminate type. Overall, 288 of 496 women (51.8%) stated that UI had a negative impact on their QoL; this effect remained mostly mild or moderate, and only 197 of 496 women (39.7%) had asked for medical help. Longer duration of symptoms, higher frequency of comorbid urinary symptoms, and altered QoL were most frequent among women with mixed UI (p<0.001). Misclassification may have occurred because the diagnosis of UI was based on self-reported data rather than on clinical or urodynamic examinations. CONCLUSIONS UI symptoms were found in almost one in four women attending GPs. Clinical and functional UI impairment were associated with age, BMI, and parity. UI caused distress to women, but only those who were severely affected sought help. The results emphasize the need for policy development for UI prevention and management in France.

Efficacy of oseltamivir-zanamivir combination compared to each monotherapy for seasonal influenza: a randomized placebo-controlled trial.

Analysis of virological and clinical outcomes from a randomized trial that was terminated early suggest that combined treatment of seasonal influenza in adult outpatients with oseltamivir plus zanamivir is no more effective than either oseltamivir or zanamivir monotherapy.

Care related pain in hospitalized patients: a cross-sectional study.

Context: Care‐related pain includes pain occurring during transportation, movement, diagnostic imaging, physical examination, or treatment. Its prevalence has never been assessed in a large adult inpatient population.

Herpes zoster: Family history and psychological stress—Case–control study

BACKGROUND Several studies have reported risk factors for herpes zoster (HZ), but their results remain controversial and difficult to compare because of their limitations regarding sampling and design. OBJECTIVES This study was aimed to determine risk factors in ambulatory patients aged 50 years or more, by consulting general practitioners (GPs) in France. STUDY DESIGN A prospective, national, matched case-control study was conducted. It involved 121 GPs who recruited 250 cases of HZ and 500 controls (matched by age and sex), aged 50 years and older, between April 2009 and September 2010. GP and patient questionnaires explored the following risk factors: family history of HZ, comorbidities, depression, anxiety, negative life events, physical trauma, alcohol and tobacco consumption, level of education, and various protective factors (such as exposure to children). Odds ratios were estimated using conditional logistic regression. RESULTS In multivariate adjusted analysis, a family history of HZ (OR 3.69, 95% CI 1.81-7.51), a HAD depressive score≥8 (OR 4.15, 95% CI 1.88-9.16), and a recent negative life event (OR 3.40, 95% CI 1.67-6.93) were all significantly associated with HZ. CONCLUSIONS This case-control study conducted in ambulatory patients in general practice reinforced the hypothesis that, in addition to the age-related decline in VZV-specific T-cell-mediated immunity, depression negative life event and familiar history of zoster increase the risk of occurrence of herpes zoster. In people with familiar history, this risk could be prevented by vaccination.

Field effectiveness of pandemic and 2009-2010 seasonal vaccines against 2009-2010 A(H1N1) influenza: estimations from surveillance data in France.

Background In this study, we assess how effective pandemic and trivalent 2009-2010 seasonal vaccines were in preventing influenza-like illness (ILI) during the 2009 A(H1N1) pandemic in France. We also compare vaccine effectiveness against ILI versus laboratory-confirmed pandemic A(H1N1) influenza, and assess the possible bias caused by using non-specific endpoints and observational data. Methodology and Principal Findings We estimated vaccine effectiveness by using the following formula: VE  =  (PPV-PCV)/(PPV(1-PCV)) × 100%, where PPV is the proportion vaccinated in the population and PCV the proportion of vaccinated influenza cases. People were considered vaccinated three weeks after receiving a dose of vaccine. ILI and pandemic A(H1N1) laboratory-confirmed cases were obtained from two surveillance networks of general practitioners. During the epidemic, 99.7% of influenza isolates were pandemic A(H1N1). Pandemic and seasonal vaccine uptakes in the population were obtained from the National Health Insurance database and by telephonic surveys, respectively. Effectiveness estimates were adjusted by age and week. The presence of residual biases was explored by calculating vaccine effectiveness after the influenza period. The effectiveness of pandemic vaccines in preventing ILI was 52% (95% confidence interval: 30–69) during the pandemic and 33% (4–55) after. It was 86% (56–98) against confirmed influenza. The effectiveness of seasonal vaccines against ILI was 61% (56–66) during the pandemic and 19% (−10–41) after. It was 60% (41–74) against confirmed influenza. Conclusions The effectiveness of pandemic vaccines in preventing confirmed pandemic A(H1N1) influenza on the field was high, consistently with published findings. It was significantly lower against ILI. This is unsurprising since not all ILI cases are caused by influenza. Trivalent 2009-2010 seasonal vaccines had a statistically significant effectiveness in preventing ILI and confirmed pandemic influenza, but were not better in preventing confirmed pandemic influenza than in preventing ILI. This lack of difference might be indicative of selection bias.

Short-term effects of airborne pollens on asthma attacks as seen by general practitioners in the Greater Paris area, 2003-2007.

AIMS To investigate for the first time the short-term effects of airborne pollen counts on general practitioner (GP) consultations for asthma attacks in the Greater Paris area between 2003-2007. METHODS Counts were available for common pollens (Betula, Cupressa, Fraxinus and Poaceae). Weekly data on GP visits for asthma attacks were obtained from the French GP Sentinel Network. A quasi-Poisson regression with generalised additive models was implemented. Short-term effects of pollen counts were assessed using single and multi-pollen models after adjustment for air pollution and influenza. RESULTS A mean weekly incidence rate of 25.4 cases of asthma attacks per 100,000 inhabitants was estimated during the study period. The strongest significant association between asthma attacks and pollen counts was registered for grass (Poaceae) in the same week of asthma attacks, with a slight reduction of the effect observed in the multi-pollen model. Adjusted relative risk for Poaceae was 1.54 (95% CI: 1.33-1.79) with an inter-quartile range increase of 17.6 grains/m3 during the pollen season. CONCLUSIONS For the first time, a significant short-term association was observed between Poaceae pollen counts and consultations for asthma attacks as seen by GPs. These findings need to be confirmed by more consistent time-series and investigations on a daily basis.

Evaluating the feasibility and participants' representativeness of an online nationwide surveillance system for influenza in France.

The increasing Internet coverage and the widespread use of digital devices offer the possibility to develop new digital surveillance systems potentially capable to provide important aid to epidemiological and public health monitoring and research. In France, a new nationwide surveillance system for influenza-like illness, GrippeNet.fr, was introduced since the 2011/2012 season based on an online participatory mechanism and open to the general population. We evaluate the recruitment and participation of users to the first pilot season with respect to similar efforts in Europe to assess the feasibility of establishing a participative network of surveillance in France. We further investigate the representativeness of the GrippeNet.fr population along a set of indicators on geographical, demographic, socio-economic and health aspects. Participation was widespread in the country and with rates comparable to other European countries with partnered projects running since a longer time. It was not representative of the general population in terms of age and gender, however all age classes were represented, including the older classes (65+ years old), generally less familiar with the digital world, but considered at high risk for influenza complications. Once adjusted on demographic indicators, the GrippeNet.fr population is found to be more frequently employed, with a higher education level and vaccination rate with respect to the general population. A similar propensity to commute for work to different regions was observed, and no significant difference was found for asthma and diabetes. Results show the feasibility of the system, provide indications to inform adjusted epidemic analyses, and highlight the presence of specific population groups that need to be addressed by targeted communication strategies to achieve a higher representativeness in the following seasons.

Disclosure of diagnosis of Alzheimer's disease in French genral practice

Most practitioners find disclosing the diagnosis of Alzheimers disease (AD) to an individual with dementia very difficult. Literature results show a wide variability in attitudes and clinical practice, and diagnosis seems to be more often disclosed to caregivers than to patients. The objective of this study was to examine whether and how diagnosis of AD is disclosed in French general practice and which issues are addressed with the patient. A questionnaire was sent via mail to 1,629 general practitioners (GPs), 1,105 belonging to the Sentinels network and 524 specially recruited doctors practicing in the Rhône-Alpes region. A total of 631 questionnaires were returned (response rate, 39 percent), of which 616 were eligible for analysis. Twenty-eight percent of GPs reported having disclosed the diagnosis to the patient (25 percent mentioned “Alzheimers disease”), whereas 88 percent considered it their role to announce the diagnosis to the patient. Regarding the type of information provided to the patient, only 25 percent discussed the nature of the illness, 23 percent behavioral problems, and 47 percent depression, mainly for psychological reasons (63 percent). Stress was discussed with 79 percent of the caregivers. We concluded that GPs do not discuss the consequences of AD and symptoms (e.g., behavioral disorders) with patients, mainly for psychological reasons, whereas they have a less-reluctant attitude toward caregivers. As the GP has the weighty task of providing appropriate community care and psychological support to the patient, it is of utmost importance to reflect on how disclosure of diagnosis can be facilitated.

Surgical Mask to Prevent Influenza Transmission in Households: A Cluster Randomized Trial

Background Facemasks and respirators have been stockpiled during pandemic preparedness. However, data on their effectiveness for limiting transmission are scarce. We evaluated the effectiveness of facemask use by index cases for limiting influenza transmission by large droplets produced during coughing in households. Methodology and Principal Findings A cluster randomized intervention trial was conducted in France during the 2008–2009 influenza season. Households were recruited during a medical visit of a household member with a positive rapid influenza A test and symptoms lasting less than 48 hours. Households were randomized either to the mask or control group for 7 days. In the intervention arm, the index case had to wear a surgical mask from the medical visit and for a period of 5 days. The trial was initially intended to include 372 households but was prematurely interrupted after the inclusion of 105 households (306 contacts) following the advice of an independent steering committee. We used generalized estimating equations to test the association between the intervention and the proportion of household contacts who developed an influenza-like illness during the 7 days following the inclusion. Influenza-like illness was reported in 24/148 (16.2%) of the contacts in the intervention arm and in 25/158 (15.8%) of the contacts in the control arm and the difference between arms was 0.40% (95%CI: −10% to 11%, P = 1.00). We observed a good adherence to the intervention. In various sensitivity analyses, we did not identify any trend in the results suggesting effectiveness of facemasks. Conclusion This study should be interpreted with caution since the lack of statistical power prevents us to draw formal conclusion regarding effectiveness of facemasks in the context of a seasonal epidemic. Trial Registration clinicaltrials.gov NCT00774774