Also, this is from the journal "Brain". It's not in a epidemiology journal. They are just neurologists describing a possible tie between a new virus and a constellation of neurological symptoms. https://academic.oup.com/brain/article/doi/10.1093/brain/awa...
They call for further study in their abstract. This is a new discovery and you want population statistics? They want population statistics, too. The NUMBERS don't exist yet, because they published this on THURSDAY.