This is pretty common, actually. https://www.verywellhealth.com/what-is-a-live-virus-vaccine-200925 https://www.verywellhealth.com/what-is-a-live-virus-vaccine

This is pretty common, actually. https://www.verywellhealth.com/what-is-a-live-virus-vaccine-200925 https://www.verywellhealth.com/what-is-a-live-virus-vaccine-... is a recent article with a partial list of common vaccines that are live. They tend to be more effective than alternative vaccines. And, unless you are immunocompromised, they are very unlikely to make you sick. What makes the polio vaccine more complicated is that it is given orally, multiplies, passes through your body, and comes out in your feces. Which gives it a route by which it can infect people other than the person who received the vaccine. The same does not happen with injected live vaccines. There is an inactivated polio vaccine that is given with a needle. That is used by the USA and most advanced countries. But it is more expensive, is harder to deliver (you need multiple shots on a schedule), and is less effective. It does protect the recipient against becoming paralyzed, but does not stop you from getting a mild stomach infection and passing it on in your feces where you can spread it to others. Therefore only the oral vaccination can halt an active community outbreak. However the fact that the oral vaccine can also START a community outbreak means that we have to be careful where we use it.