* 'A4' is a reference to RESEARCH LAB A-4, the facility Juliet accessed to steal the drug. 
* This is the same vaccine that was injected into Claire.
* The A and E stand for Adam and Eve - Damon Lindelof and Carlton Cuse said that there is an anagram, which may shed light on the Adam & Eve mystery and the wider Lost mythology.{{Source needed}}
** Possibly a future Adam & Eve born in 4993, or something to do with the year 4993. Alive for 4993 years before dying...
* According to Aaron Ze’ev Aescoly's book, Jewish Messianic Movements, a prophetic letter written to the Jews of Egypt declares that, "And in the year 4993 1233 the Messiah, son of David, will come... and kingship will return to the house of Jerusalem." Perhaps there is a Messiah coming.  Further connections to the Judo-Christian Messiah can be made, as the women of The Island cannot bear children, just as a virgin cannot bear children. According to prophecy, the Messiah will be born of a virgin.  If this vial A4993-E3 is to use to make barren women fertile, it possibly can allude to a miraculous and messianic birth.
* 4993 is the year the human race will become extinct, ( unless any one of the numbers can be changed in the equation. This was one of the objectives of DHARMA, to use the Island's unique physical properties to determine a possible different outcome.