Stir together water and sugar in a saucepan over medium-high heat. Bring to a boil and stir until the sugar dissolves.

Add cinnamon sticks and vanilla, stirring to combine. Reduce to a simmer and cook for 5 minutes covered.

Remove from heat and steep for at least 1 hour.

Strain into an airtight container. Seal and store in the refrigerator until ready to use.