Small Question on the Quarantine

Good Apocalypse to all.

The name of the Quarantine is:
Specialist [Last Name], [First Name] [MI].

Here in Italy there is a small fuss about what "MI" really means.
Some think that it means Mobile Infantry, others read it as "Middle Initial" so the name of the Quarantine should be "Specialist Donovan, Jenny S."

Can some of you america-born guys enlighten us dumb european about your funny abbreviations? ;-)

Thank you all.

Middle initial.

Yep, middle initial.

So... I lost :-P

Thank you Chris, thank you [MI] Vincent ^^

If a person has no middle name, their middle name/initial is written as NMI, for No Middle Initial.

Edit: I don't know the percentages of people who don't have middle names, though. Probably less than 10% of Americans, at a guess.

In Italy it's the exact opposite ^^
The last bit of information is wonderful.