Abstract: The devices and methods of the present invention can be used to capture and remove COVID-19 mediating nanoparticles and/or exosomes associated with COVID-19 or similar disease from the circulatory system of patients in need thereof, including those with post-COVID-19 syndrome or similar post-disease sequelae so-called “long haul” symptoms of COVID-19 or similar disease. The present invention benefits patients by providing lectin based extracorporeal methods for binding and physically removing SA RS-C7oV-2 virions, or fragments thereof, from the circulatory system. Also provided are lectin based extracorporeal methods of binding and physically removing non-viral COVID-19 mediating nanoparticles. Also disclosed herein are devices and methods for reducing the levels of biomarkers and markers of morbidity/mortality of diseases such as COVID-19 and similar diseases, including cytokines, such as IL-6, Troponin T, and D-dimer.