A favorite tactic of pro-vaccine propagandists is to dismiss the countless deaths and injuries obviously caused by vaccines by saying “correlation is not causation.”
Of course, this is only used when it suits their purpose. When it comes to disease eradication by vaccines, correlation is most definitely considered by them to be causation; that is, when a vaccine for a particular disease precedes the decline of the disease, then surely, we are told, the vaccine must be responsible.