back then they used the same "jet gun injector" which made it possible to have the blood of one person get injected into another. I remember as a kid in the 60’s we had the rubella shot that way.
Semi related story from when I was in boot camp our concern at vaccination time about the jet gun wasn't disease but that it was relatively new and those med techs who didn't have much experience with it caused problems for all. If not done right the injection would block under the skin and not go into the blood stream. Caused infections many times that happened and it wasn't a rare occasion.
Lucky for us the gun was broke that day so they had to use needles. I made up my mind not to faint if it was the last thing I ever did. Many were betting on me to be the one. Did feel dizzy for a few seconds but that passed. The biggest guy in our flight, everyone's "hero", was the one who fainted.