Charles Nuttens

Lyme borreliosis (LB) is the most common tick-borne disease in the Northern Hemisphere. In France, despite rising LB incidence, preventive measures remain limited and mainly rely on personal protective behaviors. As efforts advance toward developing an LB vaccine, it is crucial to gain a deeper understanding of public awareness, preventive practices, and vaccine acceptance. A cross-sectional online survey of French adults aged 18–65 years was conducted between November 2022 and January 2023 to collect data on sociodemographic characteristics, outdoor activity patterns, tick and LB awareness, perceived risk, preventive behaviors, and willingness to vaccinate. Among the 1803 eligible respondents, tick awareness was high (94.1%), with LB awareness slightly lower (74.5%). Among tick- and LB-aware respondents, 39.4% and 29.7% perceived themselves to be at high risk of being bitten by a tick and of contracting LB, respectively. The most common preventive behaviors were post-exposure tick checks (39.8%) and wearing protective clothing (38.5%). Concern about side effects (63.2%) and cost (42.4%) were the main barriers to vaccination. Willingness to vaccinate reached 68.3% in a hypothetical scenario in which the vaccine was both reimbursed and recommended by a healthcare professional. Our findings suggest that willingness to vaccinate against LB could be high if a future vaccine were reimbursed and supported by healthcare professionals.

Background: Respiratory syncytial virus (RSV) and influenza virus are leading causes of respiratory infections, causing substantial numbers of hospitalizations and deaths, particularly among vulnerable groups such as infants and older adults. While the burden of influenza virus infection is well-documented, the burden of RSV infection in the adult population is often underestimated due to diagnostic challenges and infrequent standard-of-care testing. This study aimed to estimate the incidence of general practitioner (GP) visits, hospitalizations, and deaths attributable to RSV and influenza virus infections in French adults aged ≥50 years, with a focus on ≥65 years, using a time-series model-based approach. In addition, costs associated with hospitalizations were calculated. Methods: Cyclic Poisson regression models and weekly data from French medical administrative databases and electronic medical records over ten epidemic seasons (2010–2020) were used to estimate incidences for RSV and influenza. The results were stratified by age group, diagnosis causes (respiratory and cardiorespiratory) and diagnosis type (primary and secondary). Average costs per hospitalization were calculated and multiplied by the number of hospitalizations estimated. Results: Among adults aged ≥65 years, we estimated RSV infection was responsible for 647 619 GP visits 24 319 hospitalizations, and 878 deaths per year. Incidence rates for GP visits for RSV were twice as large as for influenza; hospitalization rates were similar and mortality was lower. The mean annual cost of RSV-attributable hospitalizations was 105 million €, similar to influenza. Conclusions: This study highlighted the burden of RSV disease in the adult population in France is higher than previous reported. We envisage that this model-based approach will be instrumental in evaluating the impact of RSV vaccination campaigns.

Background Respiratory syncytial virus (RSV) is a leading cause of respiratory infection, causing substantial numbers of hospitalizations and deaths, particularly among vulnerable groups such as infants and older adults. However, its true burden in the adult population is often underestimated due to diagnostic challenges and infrequent standard-of-care testing. This study aimed to estimate the incidence of general practitioner (GP) visits, hospitalizations, and deaths attributable to RSV in French adults aged ≥65 years using a time-series model-based approach. In addition, costs associated with hospitalizations were calculated. Methods Cyclic Poisson regression models and weekly data from French medical administrative databases and electronic medical records over ten epidemic seasons (2010–2020) were used to estimate incidences for RSV and influenza. The results were stratified by age group, diagnosis causes (respiratory and cardiorespiratory) and diagnosis type (primary and secondary). Average costs per hospitalization were calculated and multiplied by the number of hospitalizations estimated. Results Among adults aged ≥65 years, we estimated RSV infection was responsible for 647,619 GP visits 24,319 hospitalizations, and 878 deaths per year. Incidence rates for GP visits for RSV were twice as large as for influenza; hospitalization rates were similar and mortality was lower. The mean annual cost of RSV-attributable hospitalizations was 105 million €, similar to influenza. Conclusions This study highlighted the burden of RSV disease in the adult population in France is higher than previous reported. We envisage that this model-based approach will be instrumental in evaluating the impact of RSV vaccination campaigns. Key points - The estimated incidence of RSV infection in older adult is higher than previously reported. - RSV is responsible for more GP visits, similar hospitalisations but fewer deaths compared to influenza. - Model-based studies are essential to study RSV epidemiology.

Background: Lyme borreliosis (LB) remains a public health concern in France despite improved patient management and medical care. Stay-at-home restrictions during the COVID-19 pandemic, which affected participation in outdoor recreational activities and disrupted access to health care services, may have impacted the risk of developing LB. Methods: We analyzed data from two general practitioner networks in France (Sentinel Network and an electronic medical records database [EMR]) and the national hospital discharge database to describe LB epidemiology in 2020–2021 and compare it to previous years. Google Trends’ search volume was used to evaluate the association between the population’s interest in LB and the evolving epidemiology. Results: Annual LB incidence rates in primary care decreased from 104 cases/100,000 population in 2018 to 71/100,000 in 2021 and from 82/100,000 to 60/100,000 according to Sentinel Network and EMR, respectively. Google Trends’ search volume for “Lyme” followed a similar trend, one year earlier. Annual hospitalizations were stable from 2012–2019 (1.6/100,000 on average) and declined to 1.3/100,000 in 2020 and 1.1/100,000 in 2021. This decline was observed primarily in adults ( e.g., 3.4/100,000 in 2017–2019 to 1.8/100,000 in 2020–2021 for 70–79 years of age). Changes in regional incidence rates in primary care from 2017–2019 to 2020–2021 ranged from −75% to 208%. Hospitalizations decreased in all regions except in Bretagne. Conclusions: The estimated LB incidence decreased in 2020 and 2021 compared with previous years but this change may not be related to COVID-19. The incidence decrease observed in primary care could result from reduced population interest in LB, leading to lower care-seeking behavior. The decrease in LB hospitalizations may be explained by changes in clinical practice. Surveillance systems are critical to understand the evolution of LB epidemiology. However, external factors impacting incidence estimates should be considered.

Introduction Understanding the differences between respiratory syncytial virus (RSV) subgroups A and B provides insights for the development of prevention strategies and public health interventions. We aimed to describe the structural differences of RSV subgroups, their epidemiology, and genomic diversity. The associated immune response and differences in clinical severity were also investigated. Methods A literature review from PubMed and Google Scholar (1985–2023) was performed and extended using snowballing from references in captured publications. Results RSV has two major antigenic subgroups, A and B, defined by the G glycoprotein. The RSV F fusion glycoprotein in the prefusion conformation is a major target of virus neutralizing antibodies and differs in surface exposed regions between RSV A and RSV B. The subgroups co-circulate annually, but there is considerable debate as to whether clinical severity is impacted by the subgroup of the infecting RSV strain. Large variations between the studies reporting RSV subgroup impact on clinical severity were observed. A tendency for higher disease severity may be attributed to RSV A but no consensus could be reached as to whether infection by one of the subgroup caused more severe outcomes. RSV genotype diversity decreased over the last two decades, and ON and BA have become the sole lineages detected for RSV A and RSV B, since 2014. No studies with data obtained after 2014 reported a difference in disease severity between the two subgroups. RSV F is relatively well conserved and highly similar between RSV A and B, but changes in the amino acid sequence have been observed. Some of these changes led to differences in F antigenic sites compared to reference F sequences (e.g., RSV/A Long strain), which are more pronounced in antigenic sites of the prefusion conformation of RSV B. Initial results from the second season after vaccination suggest specific RSV B efficacy wanes more rapidly than RSV A for RSV PreF-based monovalent vaccines. Conclusions RSV A and RSV B both contribute substantially to the global RSV burden. Both RSV subgroups cause severe disease and none of the available evidence to date suggests any differences in clinical severity between the subgroups. Therefore, it is important to implement measures effective at preventing disease due to both RSV A and RSV B to ensure impactful public health interventions. Monitoring overtime will be needed to assess the impact of waning antibody levels on subgroup-specific efficacy.

Introduction: Lyme borreliosis (LB) is a growing public health concern requiring accurate and comprehensive epidemiological knowledge to inform health care interventions. This study compared the epidemiology of LB in primary care and hospital settings, using for the first time in France three sources of data, and highlighted specific populations at higher risk of developing LB. Methods: This study analyzed data from general practitioner networks ( i.e ., Sentinel network, Electronic Medical Records [EMR]) and the national hospital discharge database to describe the LB epidemiology from 2010 to 2019. Results: The average annual incidence rates of LB in primary care increased from 42.3 cases/100,000 population in 2010–2012 to 83.0/100,000 in 2017–2019 for the Sentinel Network and 42.7/100,000 to 74.6/100,000 for the EMR, following a marked rise in 2016. The annual hospitalization rate remained stable from 2012 to 2019 fluctuating between 1.6 and 1.8 hospitalizations/100,000. Women were more likely to present with LB in primary care setting compared with men (male-to-female incidence rate ratio [IRR] = 0.92), whereas men were predominant among hospitalizations (IRR = 1.4), with the largest discordance among adolescents aged 10–14 years (IRR = 1.8) and adults aged 80 years and older (IRR = 2.5). In 2017–2019, the average annual incidence rate peaked among persons aged 60–69 years in primary care (>125/100,000) and aged 70–79 years among hospitalized patients (3.4/100,000). A second peak occurred in children aged 0–4 or 5–9 years depending on sources. Incidence rates in Limousin and the north-eastern regions were the highest for both primary care and hospital settings. Conclusions: Analyses showed disparities in the evolution of incidence, sex-specific incidence rates, and predominant age groups between primary care and hospital settings that merit further exploration.

Background: Invasive meningococcal disease (IMD) epidemiology has fluctuated over the past 25 years and varies among serogroups, age groups and geographical locations. Aim: This study analysed the evolution of European IMD epidemiology from 2008 to 2017 to identify trends. Methods: Reported number of IMD cases and associated incidence were extracted from the European Centre for Disease Prevention and Control Surveillance Atlas for Infectious Diseases for individual European countries. Epidemiology and its evolution were analysed by serogroup and age group. Results: Overall IMD incidence decreased by 34.4% between 2008 and 2017. Serogroup B remained predominant in 2017; despite a 56.1% decrease over the 10-year period, the rate of decrease has slowed in recent years and varies by age group. Serogroup C was the second most prevalent serogroup until 2016. Its incidence decreased among individuals aged 1–24 years, the main population targeted by MenC vaccination campaigns, but increases have occurred in other age groups. Incidences of serogroups W and Y were low but increased by > 500% and > 130% (to 0.10 and 0.07/100,000) respectively, from 2008 to 2017. Considering all serogroups, a marked modification of the evolution trends by age group has occurred, with increases in incidence mainly affecting older age groups. Conclusion: Although the overall IMD incidence decreased in Europe between 2008 and 2017, increases were observed for serogroups W and Y, and in the older population when considering all serogroups. It may be necessary to adapt current vaccination strategies to reflect epidemiological changes and their likely future evolution.