The COVID-19 convalescents had significantly elevated immunoglobulins, Orosomucoid 2 (ORM2), peroxiredoxin-2 (PRDX2), hemoglobin subunits (HBD, HBB and HBA1), as well as proteins involved in cholesterol transport such as cholesteryl ester transfer protein (CETP) and apolipoprotein A1 (APOA1). Here, HBB is linked to COVID-19.