Isn' that how you end up with a leaky vaccine? https://en.wikipedia.org/wiki/Marek%27s_disease https://en.wikipedia.org/wiki/Marek%27s_disease While it seems r

Isn' that how you end up with a leaky vaccine? https://en.wikipedia.org/wiki/Marek%27s_disease https://en.wikipedia.org/wiki/Marek%27s_disease While it seems rare, it also seems like a much deadlier outcome.