Preexposure prophylaxis for HIV is a drug that reduces the risk for an HIV-negative person to acquire HIV if taken prior to sex. It has been suggested that it is important for resource allocation decisions that there are alternatives (such as abstinence, masturbation, etc.) for individuals potentially benefitted by this prophylaxis. In this paper we explore this idea from an ethical perspective in relation to three notions often discussed in priority setting ethics, namely responsibility, outcomes, and severity of disease. While the relevance of alternatives may be explained in terms by responsibility-sensitive priority setting, such a view comes with several challenges. We then discuss two other ways in which this intuition could be better explained: (a) in terms of total outcome of health, and (b) in terms of severity of the condition.