When I was a kid, they had developed the oral variant already. I still remember my mom taking me to a place where I had to eat a lump of sugar a couple of times. I didn’t complain even though it tasted a bit odd.
The oral vaccine used a live, attenuated virus. It was slightly contagious: For a short time after vaccination, you could actually pass the vaccine virus to other people, conferring immunity even among unvaccinated people.
It also had a slight risk of causing polio. The attenuated virus could mutate, either in the vaccinated person, or in people subsequently infected. The risk was a tiny fraction that of the wild virus, so it was considered to be acceptable.
But then we (nearly) eradicated the wild variant.
Because fewer and fewer people were exposed to it in the wild, the risk of contracting paralytic polio from the virus fell below the risk of contracting it from the oral vaccine. We abandoned the oral vaccine about 20 years ago in the US.
AFAIK, an improved, more genetically stable oral vaccine is still used in certain regions with lower vaccination rates.
When I was a kid, they had developed the oral variant already. I still remember my mom taking me to a place where I had to eat a lump of sugar a couple of times. I didn’t complain even though it tasted a bit odd.
Apparently oral one is less effective. I got the shot even as an adult because the gov said it’s back now and is mandatory for certain things.
The oral vaccine used a live, attenuated virus. It was slightly contagious: For a short time after vaccination, you could actually pass the vaccine virus to other people, conferring immunity even among unvaccinated people.
It also had a slight risk of causing polio. The attenuated virus could mutate, either in the vaccinated person, or in people subsequently infected. The risk was a tiny fraction that of the wild virus, so it was considered to be acceptable.
But then we (nearly) eradicated the wild variant.
Because fewer and fewer people were exposed to it in the wild, the risk of contracting paralytic polio from the virus fell below the risk of contracting it from the oral vaccine. We abandoned the oral vaccine about 20 years ago in the US.
AFAIK, an improved, more genetically stable oral vaccine is still used in certain regions with lower vaccination rates.