GPs' practices when prescribing buprenorphine in primary care: A survey among the Sentinelles network.

INTRODUCTION: France is a leading country for opioid agonist treatment providing, with a predominance of buprenorphine. General practitioners (GPs) are the main prescribers of buprenorphine, but they seem to be less involved over the last 10 years. This work is the second part of a larger study analysing buprenorphine prescribing among French GPs working in primary care, and aims to describe GPs' practices when prescribing buprenorphine. METHODS: This is a cross-sectional study conducted in France from March to July 2021 among a sample of GPs in the Sentinelles network, a national epidemiologic surveillance system. Data about the last situations of initiation and renewal of buprenorphine were collected. RESULTS: Among the 237 participants (34.3% response rate), 156 responded to the questionnaire about the last situation of renewal and 41 about the last situation of initiation. The last initiation occurred more than 12 months earlier for 46.3% of respondents, whereas the last renewal occurred less than 1 month ago for 68.6%. There was an over-representation of the male gender among the patients who were consulting (initiation 70.7%, renewal 68.6%). A majority of patients had an illicit opioid use disorder (initiation 78.0%, renewal 82.7%). Overall, GPs were involved in the general care of patients with opioids use disorder and in opioids harm reduction (initiation 87.8% and 82.9%, renewal 88.5% and 51.9%). CONCLUSION: Among buprenorphine prescribers, initiations were infrequent unlike renewals and involved mainly illicit opioid users.

Influenza-like illness in individuals treated with immunosuppressants, biologics, and/or systemic corticosteroids for autoimmune or chronic inflammatory disease: A crowdsourced cohort study, France, 2017-2018.

BACKGROUND: Influenza-like illness (ILI) incidence estimates in individuals treated with immunosuppressants and/or biologics and/or corticosteroid for an autoimmune or chronic inflammatory disease are scarce. We compared the ILI incidence among immunocompromised population and the general population. METHOD: We conducted a prospective cohort study during the 2017-2018 seasonal influenza epidemic, on the GrippeNet.fr electronic platform, which allows the collection of epidemiological crowdsourced data on ILI, directly from the French general population. The immunocompromised population were adults treated with systemic corticosteroids, immunosuppressants, and/or biologics for an autoimmune or chronic inflammatory disease, recruited directly on GrippeNet.fr and also among patients of the departments of a single university hospital that were asked to incorporate GrippeNet.fr. The general population consisted of adults reporting none of the above treatments or diseases participating in GrippeNet.fr. The incidence of ILI was estimated on a weekly basis and compared between the immunocompromised population and the general population, during the seasonal influenza epidemic. RESULTS: Among the 318 immunocompromised patients assessed for eligibility, 177 were included. During the 2017-2018 seasonal influenza epidemic period, immunocompromised population had 1.59 (95% CI: 1.13-2.20) higher odds to experience an ILI episode, compared to the general population (N = 5358). An influenza vaccination was reported by 58% of the immunocompromised population, compared to 41% of the general population (p < 0.001). CONCLUSION: During a seasonal influenza epidemic period, the incidence of influenza-like illness was higher in patients treated with immunosuppressants, biologics, and/or corticosteroids for an autoimmune or chronic inflammatory disease, compared to the general population.

Attitudes towards booster, testing and isolation, and their impact on COVID-19 response in winter 2022/2023 in France, Belgium, and Italy: a cross-sectional survey and modelling study.

Background: European countries are focusing on testing, isolation, and boosting strategies to counter the 2022/2023 winter surge due to SARS-CoV-2 Omicron subvariants. However, widespread pandemic fatigue and limited compliance potentially undermine mitigation efforts. Methods: To establish a baseline for interventions, we ran a multicountry survey to assess respondents' willingness to receive booster vaccination and comply with testing and isolation mandates. Integrating survey and estimated immunity data in a branching process epidemic spreading model, we evaluated the effectiveness and costs of current protocols in France, Belgium, and Italy to manage the winter wave. Findings: The vast majority of survey participants (N = 4594) was willing to adhere to testing (>91%) and rapid isolation (>88%) across the three countries. Pronounced differences emerged in the declared senior adherence to booster vaccination (73% in France, 94% in Belgium, 86% in Italy). Epidemic model results estimate that testing and isolation protocols would confer significant benefit in reducing transmission (17-24% reduction, from R = 1.6 to R = 1.3 in France and Belgium, to R = 1.2 in Italy) with declared adherence. Achieving a mitigating level similar to the French protocol, the Belgian protocol would require 35% fewer tests (from 1 test to 0.65 test per infected person) and avoid the long isolation periods of the Italian protocol (average of 6 days vs. 11). A cost barrier to test would significantly decrease adherence in France and Belgium, undermining protocols' effectiveness. Interpretation: Simpler mandates for isolation may increase awareness and actual compliance, reducing testing costs, without compromising mitigation. High booster vaccination uptake remains key for the control of the winter wave. Funding: The European Commission, ANRS-Maladies Infectieuses Émergentes, the Agence Nationale de la Recherche, the Chaires Blaise Pascal Program of the Île-de-France region.

Prescribing buprenorphine for opioid use disorder in primary care: A survey of French general practitioners in the Sentinelles network.

INTRODUCTION: Although opioid substitution coverage in France is high and patient care with buprenorphine is mainly managed by general practitioners (GPs), buprenorphine sales have been decreasing since 2011, suggesting that French GPs are prescribing less buprenorphine. Yet this possible change in GP practices has not yet been investigated. This study aimed to examine primary care GPs' opinions about buprenorphine and habits related to prescribing buprenorphine. METHODS: The study team conducted a cross-sectional survey from March 2021 to July 2021 among a sample of GPs in the Sentinelles network, a French epidemiologic surveillance system based on primary care practitioners. The study collected information about substance use disorder (SUD) training, opinions on buprenorphine, and habits related to buprenorphine prescription were collected (initiation and renewal within the past two years). FINDINGS: Among the 237 participants (34 % response rate), 15.2 % reported having had specific training for SUD management. A majority reported a very positive (16 %) or positive (63.7 %) opinion of buprenorphine. Most participants agreed (61.2 %) or strongly agreed (31.2 %) that buprenorphine was efficacious in the treatment of illicit opioid use disorder. Of the 206 GPs who reported having treated patients with opioid use disorder in the past two years, 47 (22.8 %) had initiated a buprenorphine prescription, whereas 177 (85.9 %) had renewed a buprenorphine prescription. Previous SUD training was associated with initiating buprenorphine (OR 4.66; 95 % CI [2.15-10.08]), while female gender was associated with not initiating buprenorphine prescribing (OR 0.46; 95 % CI [0.22-0.98]). CONCLUSION: A sample of French GPs who work in primary care has a positive view of buprenorphine, but the absence of SUD training among this population may be a barrier to their prescribing buprenorphine.

Epidemiology of acute gastroenteritis in France from November 2019-August 2021, in light of reported adherence to COVID-19 barrier measures.

Since the start of the COVID-19 pandemic, French health authorities have encouraged barrier measures and implemented three lockdowns to slow SARS-CoV-2 transmission. We aimed to examine the impact of these measures on the epidemiology of acute gastroenteritis (AGE) in France, from November 2019 to August 2021. We describe trends in AGE indicators from syndromic surveillance and a sentinel surveillance network. Additionally, we describe reported AGE illness data from a community based cohort, and frequencies of adherence to COVID-19 barrier measures from repeated quantitative surveys. From week 7 in 2020, all AGE indicators reached the lowest levels observed since the last decade. During the first lockdown, the median incidence rate reported by the sentinel network was 32 per 100,000 inhabitants, 1.9 times lower than the minimum registered during the 2010-2019 period. Low activity persisted until April 2021. Reported illness from the community cohort mirrored these trends. Adherence to COVID-19 barrier measures was highest during the first lockdown, coinciding with the steep decrease in AGE incidence. Among children under 5 years, AGE incidence increased after the third lockdown in June and July 2021, but remained lower than previous winter-season peaks. Our study indicates that a reduction in adherence to COVID-19 barrier measures, and the end of the lockdowns, coincided with an increase in AGE incidence, particularly among young children. We therefore strongly recommend maintaining adherence to barrier measures in order to in order to limit the transmission of AGE related pathogens.

Vegetarian and Vegan Diets: Beliefs and Attitudes of General Practitioners and Pediatricians in France.

Studies suggest a decreasing trend in the consumption of meat products and a growing interest in vegetarian diets. Medical support may be relevant, especially when switching to a vegan diet. Our objective was to describe the beliefs and attitudes of primary care physicians toward vegetarian diets. A cross-sectional survey was conducted among general practitioners and pediatricians thorough a questionnaire including socio-demographic characteristics, specific care to vegetarians, and the risks and benefits of vegetarian diets according to physicians. Out of the 177 participating physicians, 104 (59%) have seen at least one vegetarian patient in consultation in the last three months. Half of the physicians declared that they would dissuade their patients from switching to a vegan diet (n = 88, 51%) and 14% (n = 24) from switching to an ovo-lacto-vegetarian (OLV) diet. Most physicians (n = 141, 88%) did not feel informed enough about these diets. Physicians thought that the most frequent deficiencies for OLV and vegan diets were iron (76% and 84%, respectively) and protein (45% and 79%, respectively). These results highlight the fact that French primary care physicians feel concerned by this subject and need more information on these diets. Specific recommendations would be useful to support their practice and relationship with vegetarians.

Pertussis surveillance results from a French general practitioner network, France, 2017 to 2020.

IntroductionIn France, three complementary surveillance networks involving hospitals and paediatrician practices currently allow pertussis surveillance among infants (<1 year old) and children (1-12 years old). Data on incidences among adolescents (13-17 years old) and adults (≥ 18 years) are scarce. In 2017, a sentinel surveillance system called Sentinelles network, was implemented among general practitioners (GPs).AimThe purpose of Sentinelles network is to assess pertussis incidence, monitor the cases' age distribution and evaluate the impact of the country's vaccination policy. We present the results from the first 4 years of this surveillance.MethodsGPs of the French Sentinelles network reported weekly numbers of epidemiologically or laboratory-confirmed cases and their characteristics.ResultsA total of 132 cases were reported over 2017-2020. Estimated national incidence rates per 100,000 inhabitants were 17 (95% confidence interval (CI): 12-22) in 2017, 10 (95% CI: 6-14) in 2018, 15 (95% CI: 10-20) in 2019 and three (95% CI: 1-5) in 2020. The incidence rate was significantly lower in 2020 than in 2017-2019. Women were significantly more affected than men (83/132; 63% of women, p = 0.004); 66% (87/132) of cases were aged 15 years or over (median age: 31.5 years; range: 2 months-87 years). Among 37 vaccinated cases with data, 33 had received the recommended number of doses for their age.ConclusionsThese results concur with incidences reported in other European countries, and with studies showing that the incidences of several respiratory diseases decreased in 2020 during the COVID-19 pandemic. The results also suggest a shift of morbidity towards older age groups, and a rapid waning of immunity after vaccination, justifying to continue this surveillance.

Seasonal influenza vaccination in pharmacy in France: description and determinants of the vaccinated at-risk population using this service, 1 year after implementation.

OBJECTIVES: Vaccination of the at-risk population against influenza by pharmacists was widely implemented in France in 2019. Only little data are available about the population using this service. We have explored the characteristics and determinants of the at-risk population vaccinated in pharmacy through a web-based cohort during the 2019-20 winter season. METHODS: This study is based on the data of the profile survey of at-risk over-18 vaccinated participants of the cohort GrippeNet.fr, for the 2019-20 winter season. Population characteristics were described using the inclusion questionnaire data. Factors associated with pharmacy influenza vaccination were analysed through a logistic regression model. KEY FINDINGS: In total, 3144 people were included in the study. 50.2% (N = 1577) of them were women and 65.5% (N = 2060) were over 65 years old. 29.5% (N = 928) of participants were vaccinated in pharmacy. 73.1% (N = 678) of participants vaccinated in pharmacy were over 65 years old and 46.6% (N = 432) had a treatment for one or more chronic disease. Factors positively associated with being vaccinated by a pharmacist were: being a man (OR = 1.25, 95% confidence interval [1.06-1.47]), being over 65 years old (OR = 1.97 [1.49-2.63]), living in a test region (OR = 1.62 [1.29-2.02] and 1.72 [1.43-2.07] depending on the year of the implementation of the experimentation) and being vaccinated against influenza in 2018/2019 (OR = 1.71 [1.32-2.21]). Factors negatively associated were: taking a chronic treatment (OR = 0.83 [0.70-0.97]), and living alone (OR = 1.40 [1.17-1.67] and being in contact with sick people (OR = 0.68 [0.50-0.93]). CONCLUSIONS: This study confirmed some factors associated with pharmacy influenza vaccination and feeds the debate on other uncertain factors. These findings can support public health authorities' willingness to enhance pharmacists' involvement in the future country-wide vaccination campaign. Our study also highlights the necessity to further investigate the impact of this measure in a few years.

Perceived risk of opioid use disorder secondary to opioid analgesic medication use by the general population in France.

BACKGROUND: In Europe and France, the use of opioid analgesic drugs has become widespread as an option for pain management. However, their use can lead to nonmedical use and/or opioid use disorder (OUD). This work aimed to assess the perceived risk of OUD secondary to opioid analgesic drugs use by the general population. METHODS: We conducted a cross-sectional observational study using the GrippeNet web-based cohort, comprising about 10,000 French volunteers from the general population, using a self-administered questionnaire. The main outcome was the perceived risk of OUD secondary to opioid analgesic drugs use, assessed by a 4-item scale and modelled using logistic regression (backward procedure). RESULTS: Among 5046 French respondents, after adjustment, 65% believed that the use of analgesic drugs could likely or very likely lead to OUD. Factors associated with the perception of a higher risk were being over 50 and having heard about opioids in the media. Previous opioid use and a high level of education decreased the perception of the risk. Among those having used opioids in the past 2 years (N = 1770), 71.1% reported being not at all concerned by this risk. The majority of the sample perceived the risk of OUD but those having already used opioid analgesics drugs expressed no concern about this risk for themselves. CONCLUSIONS: This finding highlight the need to reinforce warning on the package insert documents, therapeutic education and collaborative care between the prescribing general practitioners and pharmacists to increase awareness of opioid medications users on the risk of OUD. SIGNIFICANCE: This study found that the risk of OUD secondary to opioid analgesics use is well perceived in the general population, but that those having already used opioid analgesics expressed little concern for themselves. This finding could potentially help to raise awareness of healthcare providers and policy makers on the lack of perceived risk regarding these drugs and the need to inform and identify at-risk patients in primary care.

Implementation of a top five list to identify medical overuse in general practice according to patients' viewpoint in 2019 in France.

BACKGROUND: There is a current trend to reassess the adequacy of care. Establishing top five lists by involving patients is one way to address medical overuse. The objective of this study was to establish a patients' top five list in general practice in France. The secondary objective was to identify selection criteria. METHOD: Patients from the web-based cohort GrippeNet.fr were invited to establish their top five list from 15 care procedures previously selected by general practitioners on the basis of medical overuse. The care procedures were presented on a web-interface with guides written with the help of a patient association. A questionnaire was used to explore factors that may have influenced the choices of the participants. RESULTS: In total, 691 patients established the following top five list: 1/ Prescription of antibiotics for acute bronchitis, nasopharyngitis, otitis media with effusion, or uncomplicated influenza; 2/ Prescription of benzodiazepine and benzodiazepine-like agents for insomnia, generalised anxiety and all indications for older patients; 3/ Prescription of a homeopathic treatment (Influenzinum) for flu prevention; 4/ Prescription of antitussive or expectorant agents for acute cough or acute bronchitis care; 5/ Prescription of statins for the primary prevention of cardio-vascular risk in older patients. More than 70% of participants gave importance to the recommendations, effectiveness, and tolerance of the care procedures, whereas only half considered the cost. CONCLUSION: This study is the first to establish a patient's top-five list in general practice. This list provides direction for deciding the main targets in limiting medical overuse.

Are People Optimistically Biased about the Risk of COVID-19 Infection? Lessons from the First Wave of the Pandemic in Europe.

Unrealistic optimism, the underestimation of one's risk of experiencing harm, has been investigated extensively to understand better and predict behavioural responses to health threats. Prior to the COVID-19 pandemic, a relative dearth of research existed in this domain regarding epidemics, which is surprising considering that this optimistic bias has been associated with a lack of engagement in protective behaviours critical in fighting twenty-first-century, emergent, infectious diseases. The current study addresses this gap in the literature by investigating whether people demonstrated optimism bias during the first wave of the COVID-19 pandemic in Europe, how this changed over time, and whether unrealistic optimism was negatively associated with protective measures. Taking advantage of a pre-existing international participative influenza surveillance network (n = 12,378), absolute and comparative unrealistic optimism were measured at three epidemic stages (pre-, early, peak), and across four countries-France, Italy, Switzerland and the United Kingdom. Despite differences in culture and health response, similar patterns were observed across all four countries. The prevalence of unrealistic optimism appears to be influenced by the particular epidemic context. Paradoxically, whereas absolute unrealistic optimism decreased over time, comparative unrealistic optimism increased, suggesting that whilst people became increasingly accurate in assessing their personal risk, they nonetheless overestimated that for others. Comparative unrealistic optimism was negatively associated with the adoption of protective behaviours, which is worrying, given that these preventive measures are critical in tackling the spread and health burden of COVID-19. It is hoped these findings will inspire further research into sociocognitive mechanisms involved in risk appraisal.

Underdetection of cases of COVID-19 in France threatens epidemic control.

As countries in Europe gradually relaxed lockdown restrictions after the first wave, test-trace-isolate strategies became critical to maintain the incidence of coronavirus disease 2019 (COVID-19) at low levels1,2. Reviewing their shortcomings can provide elements to consider in light of the second wave that is currently underway in Europe. Here we estimate the rate of detection of symptomatic cases of COVID-19 in France after lockdown through the use of virological3 and participatory syndromic4 surveillance data coupled with mathematical transmission models calibrated to regional hospitalizations2. Our findings indicate that around 90,000 symptomatic infections, corresponding to 9 out 10 cases, were not ascertained by the surveillance system in the first 7 weeks after lockdown from 11 May to 28 June 2020, although the test positivity rate did not exceed the 5% recommendation of the World Health Organization (WHO)5. The median detection rate increased from 7% (95% confidence interval, 6-8%) to 38% (35-44%) over time, with large regional variations, owing to a strengthening of the system as well as a decrease in epidemic activity. According to participatory surveillance data, only 31% of individuals with COVID-19-like symptoms consulted a doctor in the study period. This suggests that large numbers of symptomatic cases of COVID-19 did not seek medical advice despite recommendations, as confirmed by serological studies6,7. Encouraging awareness and same-day healthcare-seeking behaviour of suspected cases of COVID-19 is critical to improve detection. However, the capacity of the system remained insufficient even at the low epidemic activity achieved after lockdown, and was predicted to deteriorate rapidly with increasing incidence of COVID-19 cases. Substantially more aggressive, targeted and efficient testing with easier access is required to act as a tool to control the COVID-19 pandemic. The testing strategy will be critical to enable partial lifting of the current restrictive measures in Europe and to avoid a third wave.

Factors associated with influenza-like-illness: a crowdsourced cohort study from 2012/13 to 2017/18.

BACKGROUND: Influenza generates a significant societal impact on morbidity, mortality, and associated costs. The study objective was to identify factors associated with influenza-like-illness (ILI) episodes during seasonal influenza epidemics among the general population. METHODS: A prospective study was conducted with the GrippeNet.fr crowdsourced cohort between 2012/13 and 2017/18. After having completed a yearly profile survey detailing socio-demographic, lifestyle and health characteristics, participants reported weekly data on symptoms. Factors associated with at least one ILI episode per influenza epidemic, using the European Centre for Disease Prevention and Control case definition, were analyzed through a conditional logistic regression model. RESULTS: From 2012/13 to 2017/18, 6992 individuals participated at least once, and 61% of them were women (n = 4258). From 11% (n = 469/4140 in 2013/14) to 29% (n = 866/2943 in 2012/13) of individuals experienced at least one ILI during an influenza epidemic. Factors associated with higher risk for ILI were: gender female (OR = 1.29, 95%CI [1.20; 1.40]), young age (< 5 years old: 3.12 [2.05; 4.68]); from 5 to 14 years old: 1.53 [1.17; 2.00]), respiratory allergies (1.27 [1.18; 1.37]), receiving a treatment for chronic disease (1.20 [1.09; 1.32]), being overweight (1.18 [1.08; 1.29]) or obese (1.28 [1.14; 1.44]), using public transport (1.17 [1.07; 1.29]) and having contact with pets (1.18 [1.09; 1.27]). Older age (≥ 75 years old: 0.70 [0.56; 0.87]) and being vaccinated against influenza (0.91 [0.84; 0.99]) were found to be protective factors for ILI. CONCLUSIONS: This ILI risk factors analysis confirms and further completes the list of factors observed through traditional surveillance systems. It indicates that crowdsourced cohorts are effective to study ILI determinants at the population level. These findings could be used to adapt influenza prevention messages at the population level to reduce the spread of the disease.

Population perception of mandatory childhood vaccination programme before its implementation, France, 2017.

BackgroundVaccination policy in France was previously characterised by the coexistence of eight recommended and three mandatory vaccinations for children younger than 2 years old. These 11 vaccines are now mandatory for all children born after 1 January 2018.AimTo study the French population's opinion about this new policy and to assess factors associated with a positive opinion during this changing phase.MethodsA cross-sectional survey about vaccination was conducted from 16 November-19 December 2017 among the GrippeNet.fr cohort. Data were weighted for age, sex and education according to the French population. Univariate and multivariate analyses were performed to identify factors associated with a favourable opinion on mandatory vaccines' extension and defined in the '3Cs' model by the World Health Organization Strategic Advisory Group of Experts working group on vaccine hesitancy.ResultsOf the 3,222 participants (response rate 50.5%) and after adjustment, 64.5% agreed with the extension of mandatory vaccines. It was considered a necessary step by 68.7% of the study population, while 33.8% considered it unsafe for children and 56.9% saw it as authoritarian. Factors associated with a positive opinion about the extension of mandatory vaccines were components of the confidence, complacency and convenience dimensions of the '3Cs' model.ConclusionsIn our sample, two thirds of the French population was in favour of the extension of mandatory vaccines for children. Perception of vaccine safety and benefits were major predictors for positive and negative opinions about this new policy.

Opinion about seasonal influenza vaccination among the general population 3 years after the A(H1N1)pdm2009 influenza pandemic.

OBJECTIVE: To assess the opinions of the French general population about seasonal influenza vaccination three years after the A(H1N1)pdm 09 pandemic and identify factors associated with a neutral or negative opinion about this vaccination. STUDY DESIGN: The study was conducted using data collected from 5374 participants during the 2012/2013 season of the GrippeNet.fr study. The opinion about seasonal influenza vaccination was studied on three levels ("positive", "negative" or "neutral"). The link between the participant's characteristics and their opinion regarding the seasonal influenza vaccination were studied using a multinomial logistic regression with categorical variables. The "positive" opinion was used as the reference for identifying individuals being at risk of having a "neutral" or a "negative" opinion. RESULTS: Among the participants, 39% reported having a positive opinion about seasonal influenza vaccine, 39% a neutral opinion, and 22% a negative opinion. Factors associated with a neutral or negative opinion were young age, low educational level, lack of contact with sick or elderly individuals, lack of treatment for a chronic disease and taking a homeopathic preventive treatment. CONCLUSIONS: These results show that an important part of the French population does not have a positive opinion about influenza vaccination in France. Furthermore, it allows outlining the profiles of particularly reluctant individuals who could be targeted by informative campaigns.

Association between recruitment methods and attrition in Internet-based studies.

Internet-based systems for epidemiological studies have advantages over traditional approaches as they can potentially recruit and monitor a wider range of individuals in a relatively inexpensive fashion. We studied the association between communication strategies used for recruitment (offline, online, face-to-face) and follow-up participation in nine Internet-based cohorts: the Influenzanet network of platforms for influenza surveillance which includes seven cohorts in seven different European countries, the Italian birth cohort Ninfea and the New Zealand birth cohort ELF. Follow-up participation varied from 43% to 89% depending on the cohort. Although there were heterogeneities among studies, participants who became aware of the study through an online communication campaign compared with those through traditional offline media seemed to have a lower follow-up participation in 8 out of 9 cohorts. There were no clear differences in participation between participants enrolled face-to-face and those enrolled through other offline strategies. An Internet-based campaign for Internet-based epidemiological studies seems to be less effective than an offline one in enrolling volunteers who keep participating in follow-up questionnaires. This suggests that even for Internet-based epidemiological studies an offline enrollment campaign would be helpful in order to achieve a higher participation proportion and limit the cohort attrition.

The representativeness of a European multi-center network for influenza-like-illness participatory surveillance.

BACKGROUND: The Internet is becoming more commonly used as a tool for disease surveillance. Similarly to other surveillance systems and to studies using online data collection, Internet-based surveillance will have biases in participation, affecting the generalizability of the results. Here we quantify the participation biases of Influenzanet, an ongoing European-wide network of Internet-based participatory surveillance systems for influenza-like-illness. METHODS: In 2011/2012 Influenzanet launched a standardized common framework for data collection applied to seven European countries. Influenzanet participants were compared to the general population of the participating countries to assess the representativeness of the sample in terms of a set of demographic, geographic, socio-economic and health indicators. RESULTS: More than 30,000 European residents registered to the system in the 2011/2012 season, and a subset of 25,481 participants were selected for this study. All age classes (10 years brackets) were represented in the cohort, including under 10 and over 70 years old. The Influenzanet population was not representative of the general population in terms of age distribution, underrepresenting the youngest and oldest age classes. The gender imbalance differed between countries. A counterbalance between gender-specific information-seeking behavior (more prominent in women) and Internet usage (with higher rates in male populations) may be at the origin of this difference. Once adjusted by demographic indicators, a similar propensity to commute was observed for each country, and the same top three transportation modes were used for six countries out of seven. Smokers were underrepresented in the majority of countries, as were individuals with diabetes; the representativeness of asthma prevalence and vaccination coverage for 65+ individuals in two successive seasons (2010/2011 and 2011/2012) varied between countries. CONCLUSIONS: Existing demographic and national datasets allowed the quantification of the participation biases of a large cohort for influenza-like-illness surveillance in the general population. Significant differences were found between Influenzanet participants and the general population. The quantified biases need to be taken into account in the analysis of Influenzanet epidemiological studies and provide indications on populations groups that should be targeted in recruitment efforts.

Determinants of follow-up participation in the Internet-based European influenza surveillance platform Influenzanet.

BACKGROUND: "Influenzanet" is a network of Internet-based platforms aimed at collecting real-time data for influenza surveillance in several European countries. More than 30,000 European volunteers participate every year in the study, representing one of the largest existing Internet-based multicenter cohorts. Each week during the influenza season, participants are asked to report their symptoms (if any) along with a set of additional questions. OBJECTIVE: Focusing on the first influenza season of 2011-12, when the Influenzanet system was completely harmonized within a common framework in Sweden, the United Kingdom, the Netherlands, Belgium, France, Italy, and Portugal, we investigated the propensity of users to regularly come back to the platform to provide information about their health status. Our purpose was to investigate demographic and behavioral factors associated with participation in follow-up. METHODS: By means of a multilevel analysis, we evaluated the association between regular participation during the season and sociodemographic and behavioral characteristics as measured by a background questionnaire completed by participants on registration. RESULTS: We found that lower participation in follow-up was associated with lower educational status (odds ratio [OR] 0.80, 95% CI 0.75-0.85), smoking (OR 0.64, 95% CI 0.59-0.70), younger age (OR ranging from 0.30, 95% CI 0.26-0.33 to 0.70, 95% CI 0.64-0.77), not being vaccinated against seasonal influenza (OR 0.77, 95% CI 0.72-0.84), and living in a household with children (OR 0.69, 95% CI 0.65-0.74). Most of these results hold when single countries are analyzed separately. CONCLUSIONS: Given the opportunistic enrollment of self-selected volunteers in the Influenzanet study, we have investigated how sociodemographic and behavioral characteristics may be associated with follow-up participation in the Influenzanet cohort. The study described in this paper shows that, overall, the most important determinants of participation are related to education and lifestyle: smoking, lower education level, younger age, people living with children, and people who have not been vaccinated against seasonal influenza tend to have a lower participation in follow-up. Despite the cross-country variation, the main findings are similar in the different national cohorts, and indeed the results are found to be valid also when performing a single-country analysis. Differences between countries do not seem to play a crucial role in determining the factors associated with participation in follow-up.

Decreasing prolactin levels leads to a lower diving effort but does not affect breeding success in Adélie penguins.

Current research on seabirds suggests a key role of hormones in the trade-off between self-maintenance and parental investment through their influence on foraging decisions during the breeding period. Although prolactin is known to have major effects on parental care, its role in foraging behavior has rarely been investigated in seabirds to date. The aim of this study was to assess the influence of an experimental decrease in prolactin levels on foraging decisions and its consequences on breeding success in free-living seabirds. To achieve this, we implanted bromocriptine (an inhibitor of prolactin secretion) in male Adélie penguins (Pygoscelis adeliae), monitored their foraging behavior using time-depth recorders over several trips, and recorded their reproductive output. On average 8±0.5days after implantation, we showed that bromocriptine administration led to an efficient decrease in prolactin levels. However, no differences were seen in foraging trip durations between bromocriptine-implanted birds and controls. Moreover, the time spent diving and the number of dives performed per trip were similar in both groups. By contrast, all diving parameters (including diving efficiency) were negatively affected by the treatment during the first at-sea trip following the treatment. Finally, the treatment did not affect adult body condition or chick growth and survival. Our study highlights the short-term negative effect of low prolactin levels on diving effort, but indicates that a short-term and/or low-magnitude decrease in prolactin levels alone is not sufficient to modify consistently the body maintenance or the parental investment of Adélie penguins.

Effectiveness of 2012-2013 influenza vaccine against influenza-like illness in general population: estimation in a French web-based cohort.

Most of the methods used for estimating the influenza vaccine effectiveness (IVE) target the individuals who have an influenza-like illness (ILI) rather than virologically-proven influenza and access the healthcare system. The objective of this study was to estimate the 2012-2013 IVE in general French population, using a cohort of volunteers registered on GrippeNet.fr, an online surveillance system for ILI. The IVE estimations were obtained through a logistic regression, and analyses were also performed by focusing on at-risk population of severe influenza, and by varying inclusion period and ILI definition. Overall, 1996 individuals were included in the analyses. The corrected IVE was estimated to 49% (20 to 67) for the overall population, and 32% (0 to 58) for the at-risk population. Three covariables appeared with a significant effect on the occurrence of at least one ILI during the epidemic: the age (P = 0.045), the presence of a child in the household (P<10(-3)), and the frequency of cold/flu (P<10(-3)). Comparable results were found at epidemic peak time in the hypothesis of real-time feed of data. In this study, we proposed a novel, follow-up, web-based method to reveal seasonal vaccine effectiveness, which enables analysis in a portion of the population that is not tracked by the health care system in most VE studies.