As kids in the 1960’s, we took our vaccines at school dropped on sugar cubes. Off-topic— I knew a boy who was born too early for the polio vaccine. He survived, but his legs are withered. Opted for crutches only, so he could build-up his upper body. A strong and successful professional, he and his wife recently retired and live not far from President Trump.
Polio is a fecal-oral transmission virus that had already evolved tp survive and attack through the gut. The liquid vaccine on the cubes was a weakened virus vaccinhe.
They swtched to the injectable because the weakened virus sometimes mutated while passing through the gut and caused outbreaks. The injectable is killed virus.
My dad was a polio survivor and we got vaxxed six ways from Sunday as kids.