Defense advanced research programs agency (darpa) hired moderna in 2013 to do a project for ADEPT:

https://www.darpa.mil/program/autonomous-diagnostics-to-enable-prevention-and-therapeutics

From the spec sheet:

"These tools—primarily coded genetic instructions to the body on how to produce its own protective antibodies against a specific threat—have the advantages of being easily manufactured at scale using largely synthetic processes, transported and stored without many of the cold-chain logistics required by traditional medical countermeasures, delivered with near-immediate efficacy, and safely expressed in the body for only a limited duration, causing no permanent alteration to the genome."

the idea was the soldier can go in a pathogen risk area already carry anti bodies for the known pathogen, and design the "coding" quickly, distribute it cheaply etc.

Also see DARPA Pandemic Prevention Platform....

These are not vaccines and the recurring booster is in the spec sheet why no one was told.....