I remember somebody arguing during the scamdemic that 'fe' referred to iron, as in iron in the blood.
From memory they made a persuasive case at the time, that it was iron x 2 and had something to do with 'covid' itself or the vaccine.
Bottom line: Who the hell knows?!
Could have just been an innocent typo, but probably not, and more likely a 'plausible deniability' typo (for whatever reason).
Great work. π