BackgroundThe newly developed mRNA-based COVID-19 vaccines can provoke anaphylaxis, possibly induced by polyethylene glycol (PEG) contained in the vaccine. The management of persons with a history of PEG allergy or with a suspected allergic reaction after the first dose remains to be defined.MethodsIn this real-life study, we defined two cohorts of individuals: one pre-vaccination including 187 individuals with high-risk profiles for developing anaphylaxis and a second post-vaccination including 87 individuals with suspected allergic reactions after the COVID-19 mRNA vaccine. Upon negative skin test with an mRNA vaccine, a two-step (10–90%) vaccination protocol was performed. Positive skin tests were confirmed with the basophil activation test (BAT).ResultsAmong 604,267 doses of vaccine, 87 suspected allergic reactions (5 after the booster) were reported to our division for further investigations: 18/87 (21%) were consistent with anaphylaxis, 78/87 (90%) were female, and 47/87 (54%) received the BNT162b2 mRNA vaccine. Vaccine skin tests were negative in 96% and 76% of the pre- and post-vaccination cohorts, respectively. A two-step vaccination was tolerated in 232/236 (98%) of individuals with negative tests. Four individuals experienced isolated asthmatic reactions during the two-step challenge. Vaccine-positive skin tests were consistently confirmed by BAT; CD63 and CD203c expression was selectively inhibited with ibrutinib, suggesting an IgE-dependent mechanism.ConclusionSensitization to SARS-CoV-2 mRNA vaccines can be detected with intradermal testing. Significantly more individuals were sensitized to mRNA vaccines in the post-vaccination cohort. A two-step 10–90%-vaccination protocol can be safely administered upon negative skin testing.

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Les directives traditionnelles stipulent qu'un développement musculaire nécessite un entraînement avec une charge minimale correspondant à 70 % du maximum d'une répétition (1RM). Cepen dant, des preuves récentes suggèrent que l'entraînement à faible charge (2040 % de 1RM), combiné à une restriction modérée du flux sanguin (Blood Flow Restriction, BFR), peut également entraîner des améliorations de la masse et de la force musculaires. Alors que le BFR a d'abord été principalement étudié sur des populations cliniques, de nouveaux travaux rapportent son efficacité en milieu sportif. Cet article présente les mécanismes, les méthodes, les protocoles, les risques ainsi que les effets connus du BFR. Exercise training with blood flow restriction : mechanisms and applicationsTraditional guidelines state that substantial muscle development requires training at least 70% of the one-repetition maximum (1RM) load. However, recent evidence has proven that low load training (20-40 % 1RM) combined with moderate blood flow restriction (BFR) can also lead to improvements in muscle mass and strength. While BFR has primarily been studied in clinical populations, emerging evidence demonstrates the effectiveness of BFR in sport. This article displays the mechanisms, methods, protocols, risks, and known effects of BFR. La pression optimale dépend de plusieurs caractéristiques ; d'une part, la forme et la largeur/longueur du brassard, le