COVFEFE
Decode:
COV = Corona Virus
FE stands for Ferrum
Ferrum is Iron.
Ferrum in chemistry is abbreviated to Fe.
Fe = iron
FeFe is MORE iron.
Adrenochrom use leads to iron deposits in the body, e.g. in the eyes, because of iron overload.
Covfefe is another hint from Trump that
CoronaVirus (the COV in Covfefe) leads to Fe (=Fe/ iron) overload (fefe) in AC-users.
Covfefe is a Corona Virus that attacks people with too much iron in the body, when they consume blood.