Truthfully, alcohol hasn’t been scientifically proven to be bad for vaccination.
There is no clinical evidence to support that alcohol renders COVID-19 ineffective. Neither has there been any guideline issued by the WHO, CDC or other medical boards about the same.
Alcohol intake doesn’t also directly affect the production of antibodies, which are produced by the vaccine to protect against future infection strikes. No vaccines right now have been studied in accordance with alcohol impact.
Therefore, there is no reason for people to worry about being forced to turn into teetotalers or doubt taking the vaccines.
That being said, reducing or limiting your alcohol intake and other additives, in general, may be a good idea, and on paper, boost your chances of having a healthy response to the given vaccine.