I’m not qualified to state method of application with any authority, however one guess is that a lysate might be produced from processed virus cells if that is possible.
If one could assemble enough viral material, possibly even a blend if viral materials to cover multiple strains, and process it (maybe like tumor processing ir maybe different) and pulse the immature DCs, then that would be similar to the cancer approach.
The company that dstock posted a link to seems to already include virus(HIV) in their plans so they may be a good place to look for information on their approach?