Could also be that the data set didn’t distinguish between unvaccinated and those who got one shot but didn’t compete the process. If it’s a two-dose vaccine regimen and you don’t the second, you’re effectively unvaccinated, right?
Then why state a distinction in the title of that column, if unvax and partial vax are essentially the same? If the data set didn't distinguish, then that seems to be a fault with the data collection. Again, I just find it odd. Shouldn't one dose be better than no dose? This graph could be a good opportunity to showcase why someone should at least get their first dose (unless the data and resulting additional column wouldn't support that notion).