I actually don't know, but looking at current sales of both versions and Vita probably would only just beat the Wii U although not too much in it at all
Xbox One, PS4 and Switch (+ Many Retro Consoles)
'When the people are being beaten with a stick, they are not much happier if it is called the people's stick'- Mikhail Bakunin
Prediction: Switch will sell better than Wii U Lifetime Sales by Jan 1st 2018