"I have a sincerely held religious belief that prevents me from vaccination. Signed, John Doe"

Leave the onus on them to dissect your beliefs without being given any specifics. Don't hand them enough rope to hang you.

• "I'm X religion" -we talked to your leader and he said it's okay

• "Abortion" -we looked at the ingredients and think it's fine

• "Cloning is bad" -it's not cloning because it's not a whole organism

• "My pre-existing health condition" -don't be silly, is safe and effective

Just say no and mean no, and give HR what they need so they can check your box as 'Resolved'.