Association of the immunogenicity of intramuscular SARS-CoV-2 mRNA vaccination with computed tomography muscle images in patients with muscular disorders.

Backgrounds: Intramuscular mRNA vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have a low intensity and latency of antibody response in patients with muscular disorders (MDs). However, the mechanisms involved in this phenomenon remain unknown. This study aimed to clarify the mechanism of the low immunogenicity of intramuscular SARS-CoV-2 mRNA vaccination in patients with MDs.

Muscle development in healthy children evaluated by bioelectrical impedance analysis.

Objectives: This study aimed to use bioelectrical impedance analysis (BIA) to generate a new muscle density index (MDI), the MDI_BIA, to evaluate muscle development, and to demonstrate the changes that occur in the BIA-based muscle cross-sectional area index (MCAI_BIA) that accompany growth. We also sought to determine the traceability of chronological changes in the MDI_BIA and MCAI_BIA.

Methods: Healthy children (n=112) aged 8.