There are two options:
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Create the vectors in Inkscape. I tested this with geometric shapes; I don’t know if it works with more complex shapes. You can import them into Krita, provided you save the Inkscape file without layers and in Plain SVG format (I explain this in more detail at the end of this post). Or, if it doesn’t work with SVG, there’s the option to export in png format…
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Create the vectors in Krita itself in a separate file and copy them to the animation file. Then, convert them to a paint layer.