There are and will continue to be vulnerabilities and issues with Android simply because it is such an open and flexible OS and because patching is distributed between hardware manufacturers. That said, there are many good reasons to use Android devices and so maintaining security is important. The bullets at the end of this article are a great starting point:
Patch early and often
Insist on patches – push your hardware manufacturers and distributors
Try to limit your downloads to the Google Play store and verify reputations
Consider running some form of Android Anti-Virus