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Poster session 2, September 22, 2022, 12:30 PM - 1:30 PM Objectives Invasive scedosporiosis and lomentosporiosis are deadly fungal infections due to Scedosporium spp. and Lomentospora prolificans. The Scedosporiosis/lomentosporiosis Observational Study (S.O.S.) highlighted for the first time a frequent vascular involvement in these infections including aortitis and peripheral arteritis (PA). We here describe the clinical, microbiological, radiological and anatomopathological characteristics of these vascular infections. Methods We retrospectively reviewed cases of arteritis (with the exception of central nervous system arteritis) from the S.O.S. cohort and from the literature. Results Seven cases of vascular infections were identified from the S.O.S. cohort representing 24% (7/29) of the disseminated scedosporiosis/lomentosporiosis. Four cases had both aortitis and PA, 2 patients were diagnosed with PA and one patient with aortitis. A total of 9 aortitis and 4 PA cases were identified from the literature. All 20 cases were proven scedosporiosis/lomentosporiosis. The main species was S. apiospermum [60% of cases (12/20)] followed by L. prolificans [35% of cases (7/20)]. One infection was caused by both species. An underlying immunosuppression was present in 70% of the cases (14/20, with 10 cases of solid organ transplantation and 3 cases of hematologic malignancies). The main risk factor in immunocompetent patients was a previous cutaneous trauma (4/6). Interestingly, vascular involvement was identified at diagnosis of the scedosporiosis/lomentosporiosis in only half of the cases. Aortitis was mainly abdominal (8/13). Various PA localizations were reported with frequent iliac or femoral involvement (4/10). Arteritis was the only localization in only 10% (2/20) of the scedosporiosis/lomentosporiosis, other sites involved being mainly osteoarticular (10/20), and pulmonary (9/20) followed by central nervous system (5/20), cutaneous localizations (4/20), and endocarditis (4/20). Of note, three-quarters of the cases were disseminated. Aneurysmal lesion was the most frequent imaging aspect (8/11 of aortitis and 6/10 of PA) which was complicated by a rupture in half of the aortitis (4/8) and only one PA (1/6). Vascular wall thickening (2/11 of aortitis and 1/10 of PA) and perivascular abscess (1/11 and 1/10, respectively) were more rarely described. Hypermetabolism was constant on PET-CT scan when performed (6/6). When available (11/20), pathological analysis showed an invasion of the artery wall by fungal hyphae (10/11), particularly in the media and the adventice. A total of 3-months of mortality related to infection was 44% (8/18), rising to 71% (5/7) in case of fungemia. Conclusion The vascular tropism of Scedosporium spp. and L. prolificans underlies the necessity of vascular imaging in the management of these infections, especially in case of dissemination seeking in particular aneurysmal lesions of the abdominal aorta and iliofemoral arteries.

In response to the COVID-19 pandemic caused by SARS-CoV-2, governments have adopted a wide range of non-pharmaceutical interventions (NPI). These include stringent measures such as strict lockdowns, closing schools, bars and restaurants, curfews, and barrier gestures such as mask-wearing and social distancing. Deciphering the effectiveness of each NPI is critical to responding to future waves and outbreaks. To this end, we first develop a dynamic model of the French COVID-19 epidemics over a one-year period. We rely on a global extended Susceptible-Infectious-Recovered (SIR) mechanistic model of infection that includes a dynamic transmission rate over time. Multilevel data across French regions are integrated using random effects on the parameters of the mechanistic model, boosting statistical power by multiplying integrated observation series. We estimate the parameters using a new population-based statistical approach based on a Kalman filter, used for the first time in analysing real-world data. We then fit the estimated time-varying transmission rate using a regression model that depends on the NPIs while accounting for vaccination coverage, the occurrence of variants of concern (VoC), and seasonal weather conditions. We show that all NPIs considered have an independent significant association with transmission rates. In addition, we show a strong association between weather conditions that reduces transmission in summer, and we also estimate increased transmissibility of VoC.

Background Determining the etiology of aortitis is often challenging, in particular to distinguish infectious aortitis (IA) and noninfectious aortitis (NIA). This study aims to describe and compare the clinical, biological, and radiological characteristics of IA and NIA and their outcomes. Methods A multicenter retrospective study was performed in 10 French centers, including patients with aortitis between 1 January 2014 and 31 December 2019. Results One hundred eighty-three patients were included. Of these, 66 had IA (36.1%); the causative organism was Enterobacterales and streptococci in 18.2% each, Staphylococcus aureus in 13.6%, and Coxiella burnetii in 10.6%. NIA was diagnosed in 117 patients (63.9%), mainly due to vasculitides (49.6%), followed by idiopathic aortitis (39.3%). IA was more frequently associated with aortic aneurysms compared with NIA (78.8% vs 17.6%, P < .001), especially located in the abdominal aorta (69.7% vs 23.1%, P < .001). Crude and adjusted survival were significantly lower in IA compared to NIA (P < .001 and P = .006, respectively). In the IA cohort, high American Society of Anesthesiologists score (hazard ratio [HR], 2.47 [95% confidence interval {CI}, 1.08–5.66]; P = .033) and free aneurysm rupture (HR, 9.54 [95% CI, 1.04–87.11]; P = .046) were significantly associated with mortality after adjusting for age, sex, and Charlson comorbidity score. Effective empiric antimicrobial therapy, initiated before any microbial documentation, was associated with a decreased mortality (HR, 0.23, 95% CI, .08–.71]; P = .01). Conclusions IA was complicated by significantly higher mortality rates compared with NIA. An appropriate initial antibiotic therapy appeared as a protective factor in IA.

Non-pharmaceutical interventions have been implemented intermittently for more than a year in most countries of the world to mitigate COVID-19 epidemic. In France, while the vaccination campaign is progressing, the French government has decided to remove many public health restrictions such as business closure, lockdowns and curfews. Nonetheless, social distancing, mask wearing, and hand washing (also called barrier gestures) are still recommended. We utilize an age-structured compartmental SEIR model that takes into account SARS-CoV-2 waning immunity, vaccination, and increased transmissibility from variants of concern, to estimate if barrier gestures can be relaxed without causing a resurgence of severe infections. This model assumes that susceptibility to infection is a function of immunity status, which depends on initial infection severity and vaccination status. It is calibrated on confirmed COVID-19 cases from the French surveillance database, and accounts for changes in contact behaviors due to implementation of nation-wide public health policies. We study partial and full relaxation of barrier gestures occurring from August to December 2021 under various immunity duration assumptions. Maintaining application of barrier gestures appears essential to avoid a resurgence of severe infections that would exceed health care capacities, while surmounting vaccine hesitancy represents the key to consider their relaxation. Immunity duration assumptions significantly influence the short-term dynamic of the epidemic which should be considered for further modelling.

SummaryIn response to the COVID-19 pandemic caused by SARS-CoV-2, governments have adopted a wide range of non-pharmaceutical interventions (NPI). These include stringent measures such as strict lockdowns, closing schools, bars and restaurants, curfews, and barrier gestures such as mask-wearing and social distancing. Deciphering the effectiveness of each NPI is critical to responding to future waves and outbreaks. To this end, we first develop a dynamic model of the French COVID-19 epidemics over a one-year period. We rely on a global extended Susceptible-Infectious-Recovered (SIR) mechanistic model of infection that includes a dynamic transmission rate over time. Multilevel data across French regions are integrated using random effects on the parameters of the mechanistic model, boosting statistical power by multiplying integrated observation series. We estimate the parameters using a new population-based statistical approach based on a Kalman filter, used for the first time in analysing real-world data. We then fit the estimated time-varying transmission rate using a regression model that depends on the NPIs while accounting for vaccination coverage, the occurrence of variants of concern (VoC), and seasonal weather conditions. We show that all NPIs considered have an independent significant association with transmission rates. In addition, we show a strong association between weather conditions that reduces transmission in summer, and we also estimate increased transmissibility of VoC.

International audience; Non-pharmaceutical interventions have been implemented intermittently for more than a year in most countries of the world to mitigate the COVID-19 epidemic. In France, while the vaccination campaign is progressing, the French government has decided to remove many public health restrictions such as business closure, lockdowns, and curfews. Nonetheless, social distancing, mask wearing, and hand washing (also called barrier gestures) are still recommended. We utilize an age-structured compartmental SEIR model that takes into account the SARS-CoV-2 waning immunity, vaccination, and increased transmissibility from variants of concern to estimate if barrier gestures can be relaxed without causing a resurgence of severe infections. This model assumes that the susceptibility to infection is a function of immunity status, which depends on initial infection severity and vaccination status. It is calibrated on confirmed COVID-19 cases from the French surveillance database, and accounts for changes in contact behaviors due to the implementation of nation-wide public health policies. We study the partial and full relaxation of barrier gestures occurring from August to December 2021 under various immunity duration assumptions. Maintaining the application of barrier gestures appears essential to avoid a resurgence of severe infections that would exceed French health care capacities, while surmounting vaccine hesitancy represents the key to consider their relaxation. Immunity duration assumptions significantly influence the short-term dynamic of the epidemic, which should be considered for further modelling.