If survivors acquire immunity then maybe there’s a chance for inoculation the way it was done in the old days for smallpox. Dab clear pus from a recovering victims’ wound and insert it into a cut in the arm. The dead virus was in the pus and the uninfected person’s body would develop anti-bodies from the dead virus.
You are really thinking about “dead virus” innoculations. See John Ringo’s _Under a Graveyard Sky” zombie apocalypse novel.
Ebola requires just 1 virus particle to instigate a full blown infection.
Variolation (the term for what you describe) would likely initiate a new cluster of infections.
Treatments like that used to be more common before vaccines and antibiotics took over. I think antivenin is about the only thing that still uses that method, but I could be wrong.
(Antivenin is made from the blood of horses that were given low doses of snake venom and allowed to recover.)