PIVOT: PrIVate and effective cOntact Tracing

We propose, design, and evaluate PIVOT, a privacy-enhancing and effective contact tracing solution that aims to strike a balance between utility and privacy: one that does not collect sensitive information yet allowing effective tracing and notifying the close contacts of diagnosed users. PIVOT requires a considerably low degree of trust in the entities involved compared to centralised alternatives while retaining the necessary utility. To protect users’privacy, it uses local proximity tracing based on broadcasting and recording constantly changing anonymous public keys via short-range communication. These public keys are used to establish a shared secret key between two people in close contact. The three keys (i.e., the two public keys and the established shared key) are then used to generate two unique per-user-per-contact hashes: one for infection registration and one for exposure score query. These hashes are never revealed to the public. To improve utility, user exposure score computation is performed centrally, which provides health authorities with minimal, yet insightful and actionable data. Data minimisation is achieved by the use of per-user-per-contact hashes and by enforcing role separation: the health authority act as a mixing node, while the matching between reported and queried hashes is outsourced to a third entity, an independent matching service. This separation ensures that out-of-scope information, such as users’social interactions, is hidden from the health authorities, whereas the matching service does not learn users’sensitive information. To sustain our claims, we conduct a practical evaluation that encompasses anonymity guarantees and energy requirements. IEEE

CoViD-19 infection presenting as Guillain Barr syndrome

Background: The Guillain Barr syndrome (GBS) has been linked with several viral infections including CoViD-19. Description of clinical cases: 5 out of 352 patients referring to Department of Medicine for CoViD-19 infection showed neurological symptoms suggesting GBS. All patients were confirmed as SARS-CoV-2 infected by PCR on nasopharyngeal swabs. Mean age was 63.4. One was female and 4 males. In 3 cases the infection was mild, no lung involvement was found and no intensive care was required. Intensive care admission was needed in a case with bilateral interstitial pneumonia and neurological symptoms and in a patient with pulmonary embolism. All patients suffered for diffuse, severe motor and sensory involvement. In 4 cases the ranking score at admission was 4, in one was 5. Neurophysiological investigations were performed in all patients. Two cases showed an acute inflammatory demyelinating neuropathy, in 3 cases an acute axonal neuropathy was observed. An increase in proteins was detected in cerebrospinal fluid. The presence of viral- RNA for SARS-CoV-2 in the CSF resulted negative as well as the antibodies against gangliosides. Two patients were treated with dexamethasone whereas in three patients immunoglobulins were added. Neurological symptoms gradually improved in all cases, in fact, the ranking score was 3 at hospital discharge. Conclusions: Five patients showed neurological symptoms suggesting GBS. These symptoms before treatment resulted severe and improved after therapy. Further studies are needed to confirm whether the CoViD-19 can induce the clinical development of GBS.