In this issue of the journal, Steffen Flessa proposes that human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) should not be considered as exceptional when it comes to the allocation of scarce resources. He calls for “a more rational resource allocation” in developing countries and demands that antiretroviral treatment (ART) should “undergo a prioritisation process like any other health technology”. Suggesting efficiency as prioritisation criterion he claims that “... we definitely must not include ART into the basic package unless all other interventions that are more efficient than ART are financed for the entire population!” (emphasis added by the authors). This is a strong statement. HIV/AIDS has claimed many of its victims among disadvantaged groups—people living in poverty, people with poor access to medical care, people who are discriminated against because of their sexual preferences, intravenous drug users. Is HIV/AIDS really a disease like any other, or is it exceptional? There are several aspects that make HIV/AIDS stand out: the UN Human Development Report concluded that “the AIDS pandemic has inflicted the single greatest reversal in human development”. For example, life expectancy in Botswana is estimated to fall from 65 years in 1988 to 34 years in 2008 (UNDP 2005). If (as is the case in some regions) up to one third of the population in the age group 20–50 years is affected by HIV, the effects go far beyond the individual tragedies. HIV/AIDS has a strong psychological impact also on persons not (yet) affected. Without any perspective for an effective treatment, HIV-negative people might consider leaving their home region, thus contributing to an exodus. Even if one argues that no disease is exceptional because they are all located on a continuum, the least that can be said is that HIV/AIDS is situated at its worst end. And yet, there is no doubt that resources are scarce, so priorities have to be set. This will inevitably create moral dilemmas. Flessa proposes a utilitarian approach to find a way out of the specific dilemma of providing—or not providing—ART in resource-poor developing countries with many competing health problems. A utilitarian approach in this context means that efficiency criteria are used to allocate resources in such a way that as many lives as possible will be saved. Fair enough. But we should not underestimate the practical problems associated with this approach. In no reallife situation will we have all the necessary information for such a far-reaching decision, neither on quality-adjusted life years (QALYs) (or comparable indicators) nor on costs. Even if we content ourselves with rough estimates, the many “feedback loops” to which Flessa rightly refers, e.g. growing resistance or changes in sexual behaviour and their consequences, are difficult, or rather impossible, to model. In consequence, point estimates will have rather wide confidence ranges. This is a problem that will only be slightly mollified by more and better research. We do not say that cost-efficiency calculations should not be done. They deliver necessary and valuable information on which decisions can be based. However, not all decisions can be determined by them, even if the underlying philosophy has been accepted. J Public Health (2008) 16:151–152 DOI 10.1007/s10389-007-0163-8