When I started the app my first draft included an icon with a simple red ribbon. Easy to recognise. HIV being sadly still as stigmatised as it is, some people were seriously concerned that it would identify them as HIV positive people by only looking at the phone.
Hence the logo I eventually published the app with.
However, this logo still contains the '+ve' at the bottom right corner. Small as it is - it may still cause concern (and indeed did in some users).
Therefore, the '+ve' text will disappear in version 2.0. I hope this will address the concerns.