Hecate: abuse reporting in secure messengers with sealed sender

End-to-end encryption provides strong privacy protections to billions of people, but it also complicates efforts to moderate content that can seriously harm people. To address this concern, Tyagi et al. [CRYPTO 2019] introduced the concept of asymmetric message franking (AMF), which allows people to report abusive content to a moderator, while otherwise retaining end-to-end privacy by default and even compatibility with anonymous communication systems like Signal’s sealed sender. In this work, we provide a new construction for asymmetric message franking called Hecate that is faster, more secure, and introduces additional functionality compared to Tyagi et al. First, our construction uses fewer invocations of standardized crypto primitives and operates in the plain model. Second, on top of AMF’s accountability and deniability requirements, we also add forward and backward secrecy. Third, we combine AMF with source tracing, another approach to content moderation that has previously been considered only in the setting of non-anonymous networks. Source tracing allows for messages to be forwarded, and a report only identifies the original source who created a message. To provide anonymity for senders and forwarders, we introduce a model of "AMF with preprocessing" whereby every client authenticates with the moderator out-of-band to receive a token that they later consume when sending a message anonymously.CNS-1718135 - National Science Foundation; CNS-1801564 - National Science Foundation; OAC-1739000 - National Science Foundation; CNS-1931714 - National Science Foundation; CNS-1915763 - National Science Foundation; HR00112020021 - Department of Defense/DARPA; 000000000000000000000000000000000000000000000000000000037211 - SRI Internationalhttps://www.usenix.org/system/files/sec22-issa.pdfPublished versio

Hecate: Abuse Reporting in Secure Messengers with Sealed Sender

End-to-end encryption provides strong privacy protections to billions of people, but it also complicates efforts to moderate content that can seriously harm people. To address this concern, Tyagi et al. [CRYPTO 2019] introduced the concept of asymmetric message franking (AMF), which allows people to report abusive content to a moderator, while otherwise retaining end-to-end privacy by default and even compatibility with anonymous communication systems like Signal’s sealed sender. In this work, we provide a new construction for asymmetric message franking called Hecate that is faster, more secure, and introduces additional functionality compared to Tyagi et al. First, our construction uses fewer invocations of standardized crypto primitives and operates in the plain model. Second, on top of AMF’s accountability and deniability requirements, we also add forward and backward secrecy. Third, we combine AMF with source tracing, another approach to content moderation that has previously been considered only in the setting of non-anonymous networks. Source tracing allows for messages to be forwarded, and a report only identifies the original source who created a message. To provide anonymity for senders and forwarders, we introduce a model of AMF with preprocessing whereby every client authenticates with the moderator out-of-band to receive a token that they later consume when sending a message anonymously

A counterintuitive way to speed up pedestrian and granular bottleneck flows prone to clogging: can 'more' escape faster?

Dense granular flows through constrictions, as well as competitivepedestrian evacuations, are hindered by a propensity to form clogs. We use simulations of model pedestrians and experiments with granular disks to explore an original strategy to speed up these flows, which consists in including contact-averse entities in the assembly. On the basis of a minimal cellular automaton and a continuous agent-based model for pedestrian evacuation dynamics, we find that the inclusion of polite pedestrians amid a given competitive crowd fails to reduce the evacuation time when the constriction (the doorway) is acceptably large. This is not surprising, because adding agents makes the crowd larger. In contrast, when the door is so narrow that it can accommodate at most one or two agents at a time, our strategy succeeds in substantially curbing long-lived clogs and speeding up the evacuation. A similar eect is seen experimentally in a vibrated two-dimensional hopper flow with an opening narrower than 3 disk diameters. Indeed, by adding to the initial collection of neutral disks a large fraction of magnetic ones, interacting repulsively, we observe a shortening of the time intervals between successive egresses of neutral disks, as reflected by the study of their probability distribution. On a more qualitative note, our study suggests that the much discussed analogy between pedestrian flows and granular flows could be extended to some behavioural traits of individualpedestrians.Fil: Nicolas, Alexandre. Université Paris Sud; Francia. Centre National de la Recherche Scientifique; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ibáñez, Santiago Agustín. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Universidad Nacional de Río Negro. Sede Andina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Kuperman, Marcelo Nestor. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Universidad Nacional de Río Negro. Sede Andina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bouzat, Sebastian. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Universidad Nacional de Río Negro. Sede Andina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Live Attenuated Varicella-Zoster Vaccine in Hematopoietic Stem Cell Transplantation Recipients

AbstractHematopoietic stem cell transplantation (HSCT) recipients are at risk for varicella-zoster virus (VZV) reactivation. Vaccination may help restore VZV immunity; however, the available live attenuated VZV vaccine (Zostavax) is contraindicated in immunocompromised hosts. We report our experience with using a single dose of VZV vaccine in 110 adult autologous and allogeneic HSCT recipients who were about 2 years after transplantation, free of graft-versus-host disease, and not receiving immunosuppression. One hundred eight vaccine recipients (98.2%) had no clinically apparent adverse events with a median follow-up period of 9.5 months (interquartile range, 6 to 16; range, 2 to 28). Two vaccine recipients (1.8%) developed a skin rash (one zoster-like rash with associated pain, one varicella-like) within 42 days post-vaccination that resolved with antiviral therapy. We could not confirm if these rashes were due to vaccine (Oka) or wild-type VZV. No other possible cases of VZV reactivation have occurred with about 1178 months of follow-up. Live attenuated zoster vaccine appears generally safe in this population when vaccinated as noted; the overall vaccination risk needs to be weighed against the risk of wild-type VZV disease in this high-risk population

US201 Study: A Phase 2, Randomized Proof-of-Concept Trial of Favipiravir for the Treatment of COVID-19

Background: Favipiravir is used to treat influenza, and studies demonstrate that it has antiviral activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods: We performed a randomized, open-label, multicenter, phase 2 proof-of-concept trial of favipiravir in hospitalized adult patients with polymerase chain reaction (PCR)-positive coronavirus disease 2019 (COVID-19). Patients were randomized to standard of care (SOC) or favipiravir treatment (1800mg per os twice a day [b.i.d.] on day 1, followed by 1000mg b.i.d. for 13 days). The primary end point was time to viral clearance on day 29. Results: Fifty patients were enrolled and stratified by disease severity (critical disease, severe disease, or mild to moderate disease). Nineteen patients were censored from the event of viral clearance based on being SARS-CoV-2 PCR-negative at the study outset, being PCR-positive at day 29, or because of loss to follow-up. Data from the 31 remaining patients who achieved viral clearance show enhanced viral clearance in the favipiravir group compared with the SOC group by day 29, with 72% of the favipiravir group and 52% of the SOC group being evaluable for viral clearance through day 29. The median time to viral clearance was 16.0 days (90% CI, 12.0 to 29.0) in the favipiravir group and 30.0 days (90% CI, 12.0 to 31.0) in the SOC group. A post hoc analysis revealed an effect in the subgroup of patients who were neutralizing antibody-negative at randomization. Treatment-emergent adverse events were equally distributed between the groups. Conclusions: We demonstrate that favipiravir can be safely administered to hospitalized adults with COVID-19 and believe that further studies are warranted. ClinicalTrialsgov registration: NCT04358549

Impact of Diabetic Foot Multidisciplinary Unit on Incidence of Lower-Extremity Amputations by Diabetic Foot

Diabetis; Diabetic foot ulcer; Lower-extremity amputationsDiabetes; Úlcera del pie diabético; Amputaciones de extremidades inferioresDiabetis; Úlcera del peu diabètic; Amputacions d'extremitats inferiorsBackground: One of the most devastating complications of diabetes is diabetes-related foot disease (DFD), which is a priority for public health systems. The 2016–2020 Catalonia Health Plan aimed to reduce the incidence of total and major lower-extremity amputations (LEAs) due to DFD by 10% in the population aged 45–74 years. The aim of the present study was to compare the incidence of LEA-DFD 5 years before and after the creation of the Diabetic Foot Multidisciplinary Unit at our Hospital. Methods: We prospectively collected all cases of LEA-DFD performed at Vall d’Hebron University Hospital from 1 January 2016 to 31 December 2020. Cases of LEA-DFD performed from 1 January 2011 to 31 December 2015 were retrospectively reviewed. The incidence of LEA-DFD between these periods was compared. Results: A total of 457 LEAs due to DFD were performed in 316 patients. We observed a reduction of 27.9% [CI: 23.7–32.1%] in the incidence of total LEA in the 2016–2020 period in comparison with the period 2011–2016 (0.8 ± 0.1 vs. 1.1 ± 0.3 per 10.000 inhabitants/year, p < 0.001), as well as a reduction of 49.3% [CI: 44.6–53.9%] in the incidence of major LEA-DFD (0.15 ± 0.1 vs. 0.30 ± 0.1 per 10.000 inhabitants/year, p < 0.001). Conclusions: The implementation of a Diabetic Foot Multidisciplinary Unit resulted in a significant reduction in the rate of amputations due to DFD in the population with diabetes in North Barcelona

Profil épidémiologique de la rougeole au Mali de 2009 à 2018: Epidemiological profile of measles in Mali from 2009 to 2018

Introduction: La rougeole, maladie virale hautement contagieuse causée par un Morbillivirus, reste un important problèeme de santé publique dans de nombreux pays malgré l'existence d'un vaccin efficace. La surveillance de la rougeole est l'un des aspects clés de la lutte contre cette maladie. La présente étude avait pour objectif de décrire la mortalité et la morbidité de la rougeole au Mali entre 2009 et 2018. Méthodes: Il s'agissait d'étude transversale descriptive. Les données de surveillance de la rougeole au Mali de 2009 à 2018 ont été analysées en personne, lieu et temps. Résultats: De 2009 à 2018, le nombre de cas confirmés de rougeole était de 6461 dont 29 décès soit une létalité de 0,45%. La confirmation des cas avait été faite par le laboratoire pour 2551 cas (39,48%), par lien épidémiologique pour 3738 cas (57,85%) et cliniquement pour 172 cas (2,66%). Les enfants de moins de 5 ans représentaient 50,97% des cas et 75,86% des décès. La majorité des cas (95,71 %) n'avaient jamais été vaccinés contre la rougeole. Les incidences les plus élevées avaient été observées en 2009 (22,65 pour 100 000 hbts) et 2010 (11,81 pour 100 000 hbts). Tombouctou, Gao et Mopti avaient enregistrés les plus grands nombres de cas en 2009 et Bamako, Koulikoro et Mopti en 2010. Conclusion: La majorité des cas et des décès étaient les enfants non vaccinés de moins de cinq ans. Un renforcement du programme élargi de vaccination de routine, une riposte aux épidéemies et des stratéegies de vaccination couvrant tout le pays sont nécessaires. Introduction: Measles, a highly contagious viral disease caused by a Morbillivirus, remains an important public health problem in many countries despite the availability of an effective vaccine. Measles surveillance is one of the key aspects of measles control. The objective of this study was to describe measles mortality and morbidity in Mali between 2009 and 2018. Methods: This was a descriptive cross-sectional study. Measles surveillance data in Mali from 2009 to 2018 were analysed by person, place and time. Results: From 2009 to 2018, the number of confirmed measles cases was 6461 including 29 deaths, i.e. a case-fatality rate of 0.45%. Cases were confirmed by the laboratory for 2551 cases (39.48%), by epidemiological link for 3738 cases (57.85%) and clinically for 172 cases (2.66%). Children under 5 years of age represented 50.97% of cases and 75.86% of deaths. The majority of cases (95.71%) had never been vaccinated against measles. The highest incidences were observed in 2009 (22.65 per 100,000 inhabitants) and 2010 (11.81 per 100,000 inhabitants). Timbuktu, Gao and Mopti had the highest number of cases in 2009 and Bamako, Koulikoro and Mopti in 2010. Conclusion: The majority of cases and deaths were among unvaccinated children under five years of age. Strengthening of the routine expanded programme of immunisation, response to epidemics and nationwide immunisation strategies are needed