My co-worker sent me a file created with Photoshop CC that she swears contain vector layers with shapes in them.
I am running CS5, and the same layers are showing up as rasterized. Is this a versioning problem?
Shape layers (all versions of Photoshop prior to CS6) became actual vector layers with CS6 and later. (Might be just the cloud version of CS6, I don't recall and don't have it installed anywhere handy.)
Vector layers have true fill and stroke attributes, as opposed to shape layers, which are basically a vector mask on a colored layer.
I've not tried importing a PSD with vectors into an earlier version of Photoshop, but it would make sense that CS5 and earlier can't interpret them correctly, since the functionality is missing. If your co-worker changes them to Smart Objects before sending you the file, there possibly won't be a problem. Photoshop assumes that vector SOs are opened by Illustrator, so that's worth a try.
[Added, since the above proves not workable}: Your co-worker can copy these shape layers into Illustrator, save as .ai documents, then import as Smart Objects. Although the workflow is a bit more roundabout than working on native vector layers, it's still quick and it avoids the compatibility issue.