Same in the 80's when i walked the same line. Guys in front and back dropping. Fortunately , I wasnt one of the unlucky ones.Back in the 70's I got a shot at my Dr's office, and afterwards the Dr just stood there talking to my mom and I for a bit. Next thing I know, I'm dropping like a rock. Woke up on the floor with them over me. The Dr said "happens all the time", and that's why he stayed with us and actually caught me as I was going down.
My dad told me about the "shot lines" in the Air Force back in the 50's, where it was like a gauntlet. Everybody walking down the line and getting hit with needles on both sides all the way down the line. He said lots of guys were dropping like flies.