CRP and COVID-19: Muscle involvement can be quite nonspecific in the form of myalgia or muscle fatigue, seen in 44%–70% of COVID-19 patients in various series and cohorts (Supplementary Tables 2–4), with increased CK levels seen in about a third of admitted patients.46,105 In Wuhan, symptoms attributed to “skeletal muscle injury” were reported in 19.3% of patients with severe COVID-19 versus 4.8% with non-severe COVID-19; patients with such symptoms had lower lymphocyte counts and higher CRP levels than those who did not.48