SARS-CoV-2 spike protein induces a differential monocyte activation that may contribute to age bias in COVID-19 severity.

A strong bias related to age is observed in COVID-19 patients with pediatric subjects developing a milder disease than adults. We hypothesized that a specific SARS-CoV-2 effect conjugated with preexisting differences in the immune systems may explain this. Using flow cytometry, we investigated basal immune differences in a cohort consisting of 16 non-infected young and 16 aged individuals and further leveraged an in vitro whole blood model of SARS-CoV-2 infection so that functional differences could be mined as well. In short, blood diluted in culture media was incubated 5 or 24 h with the trimeric spike protein or controls. Following unsupervised analysis, we first confirmed that the immune lymphoid and myeloid systems in adults are less efficient and prone to develop higher inflammation than those in children. We notably identified in adults a higher CD43 lymphocyte expression, known for its potentially inhibitory role. The spike protein induced different responses between adults and children, notably a higher increase of inflammatory markers together with lower monocyte and B cell activation in adults. Interestingly, CD169, a CD43 ligand overexpressed in COVID-19 patients, was confirmed to be strongly modulated by the spike protein. In conclusion, the spike protein exacerbated the preexisting lower immune responsiveness and higher inflammatory potential in adults. Altogether, some of the markers identified may explain the marked age bias and be predictive of severity.

Results of a New Telemedicine Strategy in Traumatology and Orthopedics.

Introduction:There are few studies showing results about telemedicine strategies in traumatology and orthopedics. We present a new tele-orthopedic strategy started in 2017 at the Reloncaví Health Service in Chile. Our objective was to evaluate its efficiency and impact on the orthopedic surgery specialty care waiting times of the inhabitants of the Calbuco area.Methods:We selected two general practitioners from the Calbuco Hospital who evaluated patients on the waiting list of the specialty. Synchronous connections were made between them and one orthopedic surgeon staff at the referral hospital. Connections were conducted every 2 weeks. Four to eight cases were analyzed in each session.Results:Two hundred ninety-three (n = 293) attentions were performed between June 2017 and July 2018. Highly rural patients constituted 30%. After the first evaluation by the physicians of the Calbuco Hospital, 69.6% (204/293) of the patients' consultations were resolved. The remaining 30.4% (89 patients) were presented to the specialist by telemedicine, from which 69.7% (62) required one or more follow-up connections through tele-orthopedic and 30.3% (27) were referred for on-site assessment by a subspecialist. The waiting times of the referrals decreased on average from 201 to 40 days.Discussion:This new strategy had a significant impact on the population of Calbuco, especially for the rural population. It has been possible to significantly reduce waiting list times and optimize travel times and expenditures. Only a small percentage of patients required on-site attention by a specialist after the videoconference, exhibiting the efficiency of this strategy.