I'm not on board with your "leaky" part. From what I've read, "leaky" refers to whether a vaccine prevents the patient from spreading the virus; if it doesn't, then the virus may mutate to become more deadly to people who haven't received the treatment, since there is less evolutionary pressure on it to reduce symptom severity. This is known as Marek's Syndrome.

I'm not on board with your "leaky" part. From what I've read, "leaky" refers to whether a vaccine prevents the patient from spreading the virus; if it doesn't, then the virus may mutate to become more deadly to people who haven't received the treatment, since there is less evolutionary pressure on it to reduce symptom severity. This is known as Mark's Syndrome.