I don't think any of them have better durability. If you used the Biothrax reduced schedule of doses at 0 months, one month, 6 months (five months after second dose), 12 months (six months after third dose), and 18 months, you might be able to switch to boosting once a year before a predicted spike. That would be improbable even in the richest countries (look at how Anthrax went in the US military), so the probable solution would be not to care about infection, or to pray to the god of live attenuated nasal spray vaccines to save us all.