A correlation between variables, however, does not automatically mean that the change in one variable is the cause of the change in the values of the other variable. Causation indicates that one event is the result of the occurrence of the other event; i.e. there is a causal relationship between the two events.
Vaccine advocates often say, in the event of adverse events or serious post-vaccination injury, the relationship between vaccination and onset of the adverse event prove a correlation but not causation.
But did you know...
The same can be said for vaccine efficacy...
The World Health Organisation states that vaccines efficacy shows correlates of protection and correlates of immunity.
This means, vaccines and incidence of reduced disease are coincidental, vaccines are not the cause of reduced incidence of disease.
Source:
https://www.google.com/url?sa=t&source=web&rct=j&url=https://apps.who.int/iris/bitstream/handle/10665/84288/WHO_IVB_13.01_eng.pdf&ved=2ahUKEwj24Lml-pvwAhWsILcAHVIcByAQFjABegQIBBAC&usg=AOvVaw1dSnjDSepq4ISvencA62mv