Objectives Aim of our study was to describe the incidence and predictive factors of secondary infections in patients with COVID-19. Methods Cohort study on patients hospitalized with COVID-19 at IRCCS San Raffaele Hospital between February 25 th and April 6th, 2020 (NCT04318366). We considered secondary bloodstream (BSIs) or possible lower respiratory tract infections (pLRTIs) occurred after 48 hours since hospital admission until death or discharge. We calculated multivariable Fine-Gray models, to assess factors associated with risk of secondary infections. Results Among 731 patients, a secondary infection was diagnosed in 68 patients (9.3%): 58/731 patients (7.9%) had at least one BSI and 22/731 patients (3.0%) at least one pLRTI. Overall 28-day cumulative incidence was 16.4% (95% CI 12.4% - 21.0%). The majority of BSIs was due to gram-positive pathogens (76/106 isolates, 71.7%), specifically coagulase-negative staphylococci (53/76, 69.7%), while among gram-negatives (23/106, 21.7%) Acinetobacter baumanii (7/23, 30.4%) and Escherichia coli (5/23, 21.7%) predominated. pLRTIs were mainly caused by gram-negative pathogens (14/26, 53.8%). Eleven patients were diagnosed with putative invasive aspergillosis. At multivariable analysis, factors associated with secondary infections were low baseline lymphocyte count ( < 0.7 vs >0.7 per 10 9 /L: subdistribution hazard ratios (sdHRs) 1.93 [95% CI 1.11-3.35]), baseline PaO 2 /FiO 2 (per 100-points lower: sdHRs 1.56 [95% CI 1.21-2.04]), and intensive-care unit (ICU) admission in the first 48 hours (sdHR 2.51 [95% CI 1.04-6.05]). Conclusions Patients hospitalized with COVID-19 had a high incidence of secondary infections. At multivariable analysis, early need for ICU, respiratory failure, and severe lymphopenia, were identified as risk factors for secondary infections.

Summary A single protein, HMGB1, directs the triggering of inflammation, innate and adaptive immune responses, and tissue healing after damage. HMGB1 is the best characterized damage‐associated molecular pattern (DAMP), proteins that are normally inside the cell but are released after cell death, and allow the immune system to distinguish between antigens that are dangerous or not. Notably, cells undergoing severe stress actively secrete HMGB1 via a dedicated secretion pathway: HMGB1 is relocated from the nucleus to the cytoplasm and then to secretory lysosomes or directly to the extracellular space. Extracellular HMGB1 (either released or secreted) triggers inflammation and adaptive immunological responses by switching among multiple oxidation states, which direct the mutually exclusive choices of different binding partners and receptors. Immune cells are first recruited to the damaged tissue and then activated; thereafter, HMGB1 supports tissue repair and healing, by coordinating the switch of macrophages to a tissue‐healing phenotype, activation and proliferation of stem cells, and neoangiogenesis. Inevitably, HMGB1 also orchestrates the support of stressed but illegitimate tissues: tumors. Concomitantly, HMGB1 enhances the immunogenicity of mutated proteins in the tumor (neoantigens), promoting anti‐tumor responses and immunological memory. Tweaking the activities of HMGB1 in inflammation, immune responses and tissue repair could bring large rewards in the therapy of multiple medical conditions, including cancer.

ObjectivesTo assess the safety and efficacy of interleukin (IL)−6 blockade with sarilumab in patients with severe COVID-19 pneumonia and systemic hyperinflammation.MethodsWe conducted an open-label study of sarilumab in severe COVID-19 pneumonia (PaO2/FiO2 <300 mm Hg) with hyperinflammation (elevated inflammatory markers and serum IL-6 levels). Sarilumab 400 mg was administered intravenously in addition to standard of care and results were compared with contemporary matched patients treated with standard of care alone. Clinical improvement, mortality, safety and predictors of response were assessed at 28 days.ResultsTwenty-eight patients were treated with sarilumab and 28 contemporary patients receiving standard of care alone were used as controls. At day 28 of follow-up, 61% of patients treated with sarilumab experienced clinical improvement and 7% died. These findings were not significantly different from the comparison group (clinical improvement 64%, mortality 18%; p=NS). Baseline PaO2/FiO2 ratio >100 mm Hg and lung consolidation <17% at CT scan predicted clinical improvement in patients treated with sarilumab. Median time to clinical improvement in patients with lung consolidation <17% was shorter after sarilumab (10 days) than after standard treatment (24 days; p=0.01). The rate of infection and pulmonary thrombosis was similar between the two groups.ConclusionsAt day 28, overall clinical improvement and mortality in patients with severe COVID-19 were not significantly different between sarilumab and standard of care. Sarilumab was associated with faster recovery in a subset of patients showing minor lung consolidation at baseline.

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