I don't think it's really necessary tbh, as long as you're sensible about what you install and where you source things from, i.e avoid sideloading apps from blackmarkets etc. A lot (most) of the 'articles' you see about security issues with Android are FUD marketing.
Though for peace of mind you could always install one of the free AV from play
I use Lookout myself, though mainly for it's backup and device finder...