Viral, from my observations and experiences, is usually negative as it is. Perhaps inviral for negative, viral for either/neutral, and for positive viral, well, idk. Proviral could end up sounding like 'that which promotes viraling' instead of an actual 'positive viral'. I think this problem with the prefix can happen with other words; confusion between the purest sense of positivity, versus the support/backing/endorsement of something. Anyone know any other prefixes or ways to differentiate or address this?