NYT : 2nd case of similar bad side effect of AstraZeneca-Oxford-Chadox1-UK vaccine found. Any 3rd case and it's the end of it.
Quote : "If there are two cases, then this starts to look like a dangerous pattern,” said Mark Slifka, a vaccine expert at Oregon Health and Science University. “If a third case of neurological disease pops up in the vaccine group, then this vaccine may be done."
https://www.nytimes.com/2020/09/19/health/astrazeneca-vaccine-safety-blueprints.html