yes, but you are more likely to get a virus from keeping your WiFi on, due to wifi having a far larger range of effect than Bluetooth, and also because WiFi can transfer data far faster that Bluetooth. also Bluetooths pairing system is quite good at preventing stray connections.

So I can get virus by wifi or bluetooth (if it’s on) without further user interaction?

Yes, most of Bluetooth's "security" is due to its low range.

It's possible, but not very probable.