Upon popular demand I am now working on enabling password protection for iStayHealthy. I'll enable this first in the iPhone version, then the Android version.
For a while I have been resisting this step. My main rationale was: we have a lot of very sensitive data on the phone. E.g. mails, contacts, phone/SMS logs etc. If we imagine that all these apps were password enabled - it would render the usability of the phone quite cumbersome.
However, I do recognise that health data - and in particular data relating to HIV are very sensitive. Therefore, the new versions will include a Settings tool - from where users can enable password protection for the app should they so wish.