Syndromic Surveillance of Health Effects Due to Summer Sun Overexposure: Construction of an Indicator Based on Drug Sales in Pharmacies-Preliminary Study within the PRISME Project.

INTRODUCTION: Solar radiation is classified as a known human carcinogen. In France, people frequently ask local pharmacies to dispense products for sunburns. In the PRISME project, studying this use can be a specific and sensitive way to assess these overexposures. OBJECTIVE: This study aims to construct an indicator for monitoring healthcare consumption in pharmacies after overexposure to solar UV. METHODS: The study, conducted between July and August 2019, covered a sample of pharmacies located in coastal communities of southern France. A list of products for sunburn was defined. When one of the products on this list was sold, the customer was asked to fill out a questionnaire to determine whether the purchase was related to UV overexposure. A positive predictive value (PPV) per active ingredient was calculated. RESULTS: Overall, nine pharmacies participated in the study, and 288 questionnaires were collected. The majority of products purchased were for women (60.7%), for people aged 15 and over (78.1%), and for people not living in the department (68.9%). The most frequently purchased products were our trolamine-containing products which accounted for 53% of sales. With the exception of three products, all PPVs were greater than 0.8. CONCLUSION: The high PPV confirms the suitability of the product selection as an indicator for monitoring healthcare consumption related to solar UV overexposure. Two indicators (one sensitive and one specific) were selected to maximise the chances of identifying UV-related remedies.

Efficacy of an appearance-based and a health-based sun protection intervention on summer vacationers' behaviours, PRISME cluster randomized crossover trial, France.

OBJECTIVES: Sun-seeking vacationers are particularly vulnerable to melanoma. Appearance-based interventions (ABi) showing skin damage of ultraviolet exposure may be a promising prevention tool to improve skin protection. This study aimed to measure and compare the efficacy of an ABi and a health-based intervention (HBi) on French summer vacationers' behaviours and to identify differences between subpopulations. DESIGN: A cluster randomized crossover trial with three intervention groups (control, ABi, HBi) was conducted in eight campsites on the French Mediterranean coast in summer 2019. METHODS: 1355 vacationers of both sexes and aged 12-55 years were included and followed up after 4 days (T1) and 14 months (T2). Efficacy of interventions was evaluated using multilevel mixed-effect models comparing groups on three outcomes: self-reported sun protection behaviours, sunbathing and skin colour measures. Protection behaviours were analysed according to subpopulations. RESULTS: Compared to controls, the ABi group had a higher protection and sunbathed for fewer hours at T1 and T2. In the HBi group, the skin colour was lighter than controls at T1. When comparing ABi to HBi, ABi participants had lower exposure than HBi at T1 and T2. The protection of people with a 3-years university degree was higher in the HBi group than in others groups while that of people with a secondary school certificate was higher in the ABi group. CONCLUSIONS: Our study provides further evidence of individual sun protection interventions effect in a touristic setting and highlights the relevance of ABi messages to supplement HBi messages, particularly in certain subpopulations with low to intermediate education levels.

Cryptosporidiosis outbreaks linked to the public water supply in a military camp, France.

INTRODUCTION: Contaminated drinking and recreational waters account for most of the reported Cryptosporidium spp. exposures in high-income countries. In June 2017, two successive cryptosporidiosis outbreaks occurred among service members in a military training camp located in Southwest France. Several other gastroenteritis outbreaks were previously reported in this camp, all among trainees in the days following their arrival, without any causative pathogen identification. Epidemiological, microbiological and environmental investigations were carried out to explain theses outbreaks. MATERIAL AND METHODS: Syndromic diagnosis using multiplex PCR was used for stool testing. Water samples (100 L) were collected at 10 points of the drinking water installations and enumeration of Cryptosporidium oocysts performed. The identification of Cryptosporidium species was performed using real-time 18S SSU rRNA PCR and confirmed by GP60 sequencing. RESULTS: A total of 100 human cases were reported with a global attack rate of 27.8%. Cryptosporidium spp. was identified in 93% of stool samples with syndromic multiplex PCR. The entire drinking water network was contaminated with Cryptosporidium spp. The highest level of contamination was found in groundwater and in the water leaving the treatment plant, with >1,000 oocysts per 100 L. The same Cryptosporidium hominis isolate subtype IbA10G2 was identified in patients' stool and water samples. Several polluting activities were identified within the protection perimeters of the water resource. An additional ultrafiltration module was installed at the outlet of the water treatment plant. After several weeks, no Cryptosporidium oocysts were found in the public water supply. CONCLUSIONS: After successive and unexplained gastroenteritis outbreaks, this investigation confirmed a waterborne outbreak due to Cryptosporidium hominis subtype IbA10G2. Our study demonstrates the value of syndromic diagnosis for gastroenteritis outbreak investigation. Our results also highlight the importance of better assessing the microbiological risk associated with raw water and the need for sensitive and easy-to-implement tools for parasite detection.

Influence of Social and Psychosocial Factors on Summer Vacationers' Sun Protection Behaviors, the PRISME Study, France.

Objectives: Summer intermittent sun exposure is a major risk factor for melanoma. Socioeconomic position, cognitive and psychosocial factors play a role in sun protection behaviors but the underlying mechanisms are unknown. This study aimed to measure the influence of educational level on sun protection behaviors in French summer vacationers on the Mediterranean coastline, and to identify the mediating psychosocial factors in this pathway. Methods: In summer 2019, French vacationers aged 12-55 staying in coastline campsites were asked about their holiday sun protection behaviors, their knowledge, attitudes, perceived control, and social norm relative to sun protection. A structural equation model measured the direct and indirect effects of educational level on protection behaviors via cognitive and psychosocial factors. Results: Sun protection during vacation increased with educational level. Theoretical knowledge partially mediated this association, from 22% to 86%, particularly for intermediate educational levels. Conclusion: Our results highlight the importance of implementing suitable sun prevention interventions for vacationers, especially those with a lower socioeconomic position. Improving theoretical knowledge around sun protection may be an important part of broader efforts to encouraging improved preventive behaviors.

Estimating chikungunya virus transmission parameters and vector control effectiveness highlights key factors to mitigate arboviral disease outbreaks.

BACKGROUND: Viruses transmitted by Aedes mosquitoes have greatly expanded their geographic range in recent decades. They are considered emerging public health threats throughout the world, including Europe. Therefore, public health authorities must be prepared by quantifying the potential magnitude of virus transmission and the effectiveness of interventions. METHODOLOGY: We developed a mathematical model with a vector-host structure for chikungunya virus transmission and estimated model parameters from epidemiological data of the two main autochthonous chikungunya virus transmission events that occurred in Southern France, in Montpellier (2014) and in Le Cannet-des-Maures (2017). We then performed simulations of the model using these estimates to forecast the magnitude of the foci of transmission as a function of the response delay and the moment of virus introduction. CONCLUSIONS: The results of the different simulations underline the relative importance of each variable and can be useful to stakeholders when designing context-based intervention strategies. The findings emphasize the importance of, and advocate for early detection of imported cases and timely biological confirmation of autochthonous cases to ensure timely vector control measures, supporting the implementation and the maintenance of sustainable surveillance systems.

A Community Outbreak of Legionnaires' Disease with Two Strains of L. pneumophila Serogroup 1 Linked to an Aquatic Therapy Centre.

An outbreak of Legionnaires' disease affected 18 people in Montpellier, a town of the south of France, between December 2016 and July 2017. All cases were diagnosed by a positive urinary antigen test. No deaths were reported. Epidemiological, environmental and genomic investigations (nested Sequence-Based Typing (nSBT) and whole genome sequencing) were undertaken. For the cases for which we had information, four had a new isolate (ST2471), one had a different new isolate (ST2470), one had a genomic pattern compatible with the ST2471 identified by nSBT (flaA = 3), and one had a genomic pattern not compatible with two previous identified STs (pilE = 6). The analysis conducted on the pool of an aquatic therapy center revealed seven isolates of Legionella pneumophila. Whole genome analysis confirmed the link between the environmental and clinical isolates for both ST2470 and ST2471. As the outbreak occurred slowly, with several weeks between new cases, it was not possible to immediately identify a common source. The sixth case was the first to report having aquatic therapy care. Of the 18 cases, eight had attended the aquatic therapy center and the other 10 were inhabitants who lived, worked or walked close to the center. The main cause for this outbreak was the lack of facility maintenance. This investigation highlights the risk to public health of aquatic therapy centers for users and nearby populations, and emphasizes the need for risk reduction measures with specific guidelines to improve health and safety in aquatic facilities.

Seroprevalence of anti-SARS-CoV-2 antibodies after the first wave of the COVID-19 pandemic in a vulnerable population in France: a cross-sectional study.

OBJECTIVES: We aimed to assess the level of prior SARS-CoV-2 infection in socially deprived neighbourhoods after the first wave of the pandemic, and to identify factors associated with seropositivity. DESIGN: A cross-sectional study. SETTING: Three socially deprived neighbourhoods of the city of Perpignan, in the south of France, where large settled Roma communities live. PARTICIPANTS: People aged 6 years old or over, living in the study area. 700 people were included in the study using two-stage stratified sampling design. INTERVENTIONS: The study included a questionnaire and SARS-CoV-2 antibody testing by the Roche Elecsys immunoassay between 29 June and 17 July 2020. PRIMARY AND SECONDARY OUTCOME MEASURES: SARS-CoV-2 antibody seroprevalence was estimated from weighted data. Associated factors and reported symptoms were investigated using univariable and multivariable logistic regressions. RESULTS: The seroprevalence of anti-SARS-CoV-2 antibodies was 35.4% (95% CI 30.2% to 41.0%). People aged 15-64 years old had increased odds of being seropositive than those aged 65 years or over. Obese people had higher odds of being seropositive (adjusted OR (aOR)=2.0, 95% CI 1.1 to 3.8). The odds of being seropositive were higher in households with clinical COVID-19 cases (one case: aOR=2.5, 95% CI 1.3 to 5.0; several cases: aOR=6.9, 95% CI 3.1 to 15.2). In the neighbourhood with the highest measured seroprevalence, people living in a dwelling with one to two rooms had higher odds of being seropositive than those living in a four-room house (aOR=2.8, 95% CI 1.2 to 6.3). Working during the lockdown was associated with lower odds of being seropositive (aOR=0.2, 95% CI 0.03 to 1.0). CONCLUSION: Transmission of SARS-COV-2 in this vulnerable population was very high during the COVID-19 pandemic's first wave. Our results highlight the need to strengthen and adapt preventive measures taking into account all social determinants of health, especially housing conditions.

COVID-19 hotspots through clusters analysis in France (may-October 2020): where should we track the virus to mitigate the spread?

BACKGROUND: In France, the lifting of the lockdown implemented to control the COVID-19 first wave in 2020 was followed by a reinforced contact-tracing (CT) strategy for the early detection of cases and transmission chains. We developed a reporting system of clusters defined as at least three COVID-19 cases, within seven days and belonging to the same community or having participated in the same gathering, whether they know each other or not. The aim of this study was to describe the typology and criticality of clusters reported between the two lockdowns in France to guide future action prioritisation. METHODS: In this study we describe the typology and criticality of COVID-19 clusters between the two lockdowns implemented in France (between May and end of October 2020). Clusters were registered in a national database named "MONIC" (MONItoring des Clusters), established in May 2020. This surveillance system identified the most affected communities in a timely manner. A level of criticality was defined for each cluster to take into consideration the risk of spreading within and outside the community of occurrence, and the health impact within the community. We compared the level of criticality according to the type of community in which the cluster occurred using Pearson's chi-square tests. RESULTS: A total of 7236 clusters were reported over the study period, particularly in occupational environment (25.1%, n = 1813), elderly care structures (21.9%, n = 1586), and educational establishments (15.9%, n = 1154). We show a shift over time of the most affected communities in terms of number of clusters. Clusters reported in occupational environment and the personal sphere had increased during summer while clusters reported in educational environment increased after the start of the school year. This trend mirrors change of transmission pattern overtime according to social contacts. Among all reported clusters, 43.1% had a high level of criticality with significant differences between communities (p < 0.0001). A majority of clusters had a high level of criticality in elderly care structures (82.2%), in disability care centres (56.6%), and health care facilities (51.7%). CONCLUSION: These results highlight the importance of targeting public health action based on timely sustained investigations, testing capacity and targeted awareness campaigns. The emergence of new SARS-CoV-2 variants strengthen these public health recommendations and the need for rapid and prioritise vaccination campaigns.

Implementation of a national waterborne disease outbreak surveillance system: overview and preliminary results, France, 2010 to 2019.

BackgroundWaterborne disease outbreaks (WBDO) associated with tap water consumption are probably underestimated in France.AimIn order to improve their detection, Santé publique France launched a surveillance system in 2019, based on the periodical analysis of health insurance data for medicalised acute gastroenteritis (mAGE).MethodsSpatio-temporal cluster detection methods were applied to mAGE cases to prioritise clusters for further investigation. These investigations determined the plausibility that infection is of waterborne origin and the strength of association.ResultsBetween January 2010 and December 2019, 3,323 priority clusters were detected (53,878 excess mAGE cases). They involved 3,717 drinking water supply zones (WSZ), 15.4% of all French WSZ. One third of these WSZ (33.4%; n = 1,242 WSZ) were linked to repeated clusters. Moreover, our system detected 79% of WBDO voluntarily notified to health authorities.ConclusionEnvironmental investigations of detected clusters are necessary to determine the plausibility that infection is of waterborne origin. Consequently, they contribute to identifying which WSZ are linked to clusters and for which specific actions are needed to avoid future outbreaks. The surveillance system incorporates three priority elements: linking environmental investigations with water safety plan management, promoting the systematic use of rainfall data to assess waterborne origin, and focusing on repeat clusters. In the absence of an alternative clear hypothesis, the occurrence of a mAGE cluster in a territory completely matching a distribution zone indicates a high plausibility of water origin.

Effect of an Appearance-Based vs. a Health-Based Sun-Protective Intervention on French Summer Tourists' Behaviors in a Cluster Randomized Crossover Trial: The PRISME Protocol.

Background: Sun exposure has short- and long-term adverse effects on eyes, skin, and the immune system. The most serious effect, melanoma, is largely attributable to natural ultraviolet radiation. Its prevalence is steadily increasing in fair-skinned populations in most European countries. Despite annual prevention campaigns, the French population continues to be overexposed to the sun and under-protected. Social and psychosocial characteristics may play an important role in sun protection determinants. Overexposure is partially motivated by a desire to tan oneself for aesthetic reasons. During summer, intense exposure constitutes a major risk factor for melanoma, making tourists a particularly high-risk population. Literature reviews concluded that appearance-based interventions highlighting the aesthetic effects of sun exposure on skin photoaging showed promise in terms of improving sun-exposure and sun-protection behaviors, especially among younger people, but that more rigorous studies were needed. In this context, we implemented the PRISME study to: - identify the determinants, in particular social and psychosocial, of sun-protection of French summer tourists visiting the Mediterranean coastline; - design two prevention interventions grounded in psychosocial theories; - compare the impact of both interventions on tourists' sun-protection behaviors, and identify the determinants influencing this impact. This paper presents the methodology of the PRISME study. Methods: During summer 2019, we conducted a cluster randomized crossover trial to compare two prevention interventions, one based on health-related messages (health effects information, phototype calculation), the other on appearance-related messages (photoaging information, ultraviolet photography), among French tourists aged 12-55 years old in coastline campsites in the French region of Occitanie. Both interventions were anchored in the theory of planned behavior and in the transtheoretical model. The interventions' impact was measured using face-to-face questionnaires and skin color measurements both immediately before and 4 days after the interventions. A second follow-up, using an online questionnaire, will be conducted in September 2020 to measure the longer-term effects of both interventions. Discussion: Despite certain study limitations, PRISME take into consideration several known methodological gaps. The study's results will enable to evaluate the efficacy of the promising appearance-based approach in France, and to identify vulnerable sub-populations and mechanisms to improve sun-protection behaviors of French tourists.

Syndromic Surveillance of Acute Gastroenteritis Using the French Health Insurance Database: Discriminatory Algorithm and Drug Prescription Practices Evaluations.

The French national public health agency (Santé publique France) has used data from the national health insurance reimbursement system (SNDS) to identify medicalised acute gastroenteritis (mAGE) for more than 10 years. This paper presents the method developed to evaluate this system: performance and characteristics of the discriminatory algorithm, portability in mainland and overseas French departments, and verification of the mAGE database updating process. Pharmacy surveys with certified mAGE from 2012 to 2015 were used to characterise mAGE and to estimate the sensitivity and predictive positive value (PPV) of the algorithm. Prescription characteristics from these pharmacy surveys and from 2014 SNDS prescriptions in six mainland and overseas departments were compared. The sensitivity (0.90) and PPV (0.82) did not vary according to the age of the population or year. Prescription characteristics were similar within all studied departments. This confirms that the algorithm can be used in all French departments, for both paediatric and adult populations, with stability and durability over time. The algorithm can identify mAGE cases at a municipal level. The validated system has been implemented in a national waterborne disease outbreaks surveillance system since 2019 with the aim of improving the prevention of infectious disease risk attributable to localised tap water systems.

Waterborne Disease Outbreak Detection: A Simulation-Based Study.

Waterborne disease outbreaks (WBDOs) remain a public health issue in developed countries, but to date the surveillance of WBDOs in France, mainly based on the voluntary reporting of clusters of acute gastrointestinal infections (AGIs) by general practitioners to health authorities, is characterized by low sensitivity. In this context, a detection algorithm using health insurance data and based on a space⁻time method was developed to improve WBDO detection. The objective of the present simulation-based study was to evaluate the performance of this algorithm for WBDO detection using health insurance data. The daily baseline counts of acute gastrointestinal infections were simulated. Two thousand simulated WBDO signals were then superimposed on the baseline data. Sensitivity (Se) and positive predictive value (PPV) were both used to evaluate the detection algorithm. Multivariate regression was also performed to identify the factors associated with WBDO detection. Almost three-quarters of the simulated WBDOs were detected (Se = 73.0%). More than 9 out of 10 detected signals corresponded to a WBDO (PPV = 90.5%). The probability of detecting a WBDO increased with the outbreak size. These results underline the value of using the detection algorithm for the implementation of a national surveillance system for WBDOs in France.

Variations in trihalomethane levels in three French water distribution systems and the development of a predictive model.

Epidemiological studies have demonstrated that chlorination by-products in drinking water may cause some types of cancer in humans. However, due to differences in methodology between the various studies, it is not possible to establish a dose-response relationship. This shortcoming is due primarily to uncertainties about how exposure is measured-made difficult by the great number of compounds present-the exposure routes involved and the variation in concentrations in water distribution systems. This is especially true for trihalomethanes for which concentrations can double between the water treatment plant and the consumer tap. The aim of this study is to describe the behaviour of trihalomethanes in three French water distribution systems and develop a mathematical model to predict concentrations in the water distribution system using data collected from treated water at the plant (i.e. the entrance of the distribution system). In 2006 and 2007, samples were taken successively from treated water at the plant and at several points in the water distribution system in three French cities. In addition to the concentrations of the four trihalomethanes (chloroform, dichlorobromomethane, chlorodibromomethane, bromoform), many other parameters involved in their formation that affect their concentration were also measured. The average trihalomethane concentration in the three water distribution systems ranged from 21.6 µg/L to 59.9 µg/L. The increase in trihalomethanes between the treated water at the plant and a given point in the water distribution system varied by a factor of 1.1-5.7 over all of the samples. A log-log linear regression model was constructed to predict THM concentrations in the water distribution system. The five variables used were trihalomethane concentration and free residual chlorine for treated water at the plant, two variables that characterize the reactivity of organic matter (specific UV absorbance (SUVA), an indicator developed for the free chlorine consumption in the treatment plant before distribution δ) and water residence time in the distribution system. French regulations impose a minimum trihalomethane level for drinking water and most tests are performed on treated water at the plant. Applied in this context, the model developed here helps better to understand trihalomethane exposure in the French population, particularly useful for epidemiological studies.

Natural and technical factors in faecal contamination incidents of drinking water in small distribution networks, France, 2003-2004: a geographical study.

This geographical study aimed to show natural or water-processing-related factors of faecal contamination incidents (FCIs) of drinking water in continental France. We defined a FCI as the occurrence of at least 20 colony-forming Escherichia coli or enterococci among all the 100 mL samples collected for regulatory purpose within one day from a given drinking water supply zone (SZ). We explored correlations between the standardized number of FCIs per département (N_Pols) and various indicators related to weather, land cover, topography, geology and water management for three SZ size sub-classes. In 2003-2004, 2,739 FCIs occurred in SZs supplying fewer than 2,000 people, mainly with simply disinfected groundwater. N_Pols correlates with four covariates: (1) precipitation; (2) the extension of the karst outcrops; (3) the extent of disinfection; and (4) catchment protection. One hundred millimetres of yearly excess in precipitation increases the pollution risk by 28-37%, depending on the sub-class. A 10% extension of the karst areas, a 10% increase of unprotected resources, or of SZs with no disinfection, could entail a higher risk of FCI by about 10%. The correlations are reproducible over the three sub-classes and corroborate expert appraisals. These results encourage the ongoing effort to generalize disinfection and catchment protection.

Lessons learned from ten investigations of waterborne gastroenteritis outbreaks, France, 1998-2006.

Ten outbreaks of waterborne acute gastroenteritis (AGE) have been investigated in France since 1998. These outbreaks have affected populations of over 1,000 people, with generally high attack rates. The causal agents have been identified in six of these events. Aetiologies involved mainly noroviruses and Cryptosporidium sp. The point of entry of the contamination was located in the distribution network in five outbreaks (waste water backflows in four cases and one case of contamination induced by maintenance work) and at the water collection facilities in five other cases. Once the outbreak was detected, epidemiological and environmental investigations and crisis management followed well-established procedures. Further progress in public health surveillance will depend on more complete and rapid detection and reporting. Automated analysis of health insurance data on the reimbursement of drugs for AGE should help make detection more complete. Improved reactivity depends primarily on the operator immediately reporting incidents that indicate a possible massive contamination of the water network to health authorities - in particular complaints from the population, which are the only early-warning alerts in the case of waste water backflows.