HIV prevalence in Uganda has leveled off, however trends indicate that incidence 
is on the rise and disproportionately affects certain vulnerable groups, such as 
women. There is growing support for using mobile health (mHealth) programs to 
reach vulnerable populations. Using the Extended Technology-Community-Management 
model for mHealth, we examined a text message campaign in Arua, Uganda, that 
disseminated and measured HIV/AIDS knowledge and promoted HIV/AIDS testing at 
clinics. Empirical data from this campaign illustrated that mHealth campaigns 
need to address socio-cultural, informational, economic and individual 
vulnerabilities. We found, for example, that the interactive SMS quiz design 
motivated recipients with the correct HIV/AIDS knowledge to respond (and thus 
become eligible for free HIV screening). In doing so, however, the more 
vulnerable sections of the population, such as those with incorrect knowledge, 
were further put at risk. We discuss the programmatic implications and provide 
strategic recommendations for campaign focus, particularly to reach young women.