AIDS Research and Treatment will be to avoid stock shortages and wastages. Endemic HIV-2 complicates the program. The numbers of HIV-2 patients needing ART are harder to estimate and may vary with changes in testing algorithms (see Section 4.1). As HIV-2 patients on ART will represent a small minority of a program or project’s total number of HIV patients, small ﬂuctuations in their number result in disproportionately large ﬂuctuations in utilization rate, a situation that is further exacerbated for second-line treatment and pediatric cohorts. Stock management for pediatric cohorts with their heterogeneity in terms of weight, physical maturity, and ability to swallow pills is particularly diﬃcult, and pediatric HIV-2 cohorts are likely to be extremely small. Partial standardization across both HIV-1 and HIV-2 regimens, for example using the same NRTIs regardless of HIV type or using the same PI for HIV-2 ﬁrst-line treatment that one uses for HIV-1 second-line treatment, may simplify stock management and reduce shortages and wastage. Another factor aﬀecting ART choices in West Africa is cost. While costs can be expected to vary over time and between countries or regions, representative daily costs for several combinations, primarily from West Africa in 2010, are given in Table 2, although neither the costs nor the ratios of costs that follow should be presumed to be static. Compared with AZT, TDF and ddI are 2-3 times and ABC 4-5 times as expensive, while d4T costs half to one-third as much. The most expensive part of the regimen is the boosted PI, and this is also the main source of cost diﬀerences between regimens. Compared to coformulated LPV/r, SQV/r is 5–7 times and DRV/r 14–23 times as expensive, while IDV/r is approximately of the same cost. Comparisons of costs should also take eﬃcacy into account. Depending on the model and assumptions this may result in medicines with a higher daily cost being more cost-eﬀective, as has been recently shown for TDF in ﬁrst-line ART in India [115]. 4.5. Training and Protocol Development. The diﬀerences in recommendations between HIV-1 and HIV-2 and the dosing complications, particularly with TB cotreatment and in late pregnancy, pose further challenges to front line staﬀ involved in program implementation in the HIV-2 endemic areas of West Africa. More complicated protocols call for more detailed training of staﬀ. Greater diagnostic ambiguity and a broader range of ART regimens require more complete medical records. Finally patients getting information from various sources, especially long-term nonprogressors, need additional counseling to understand their disease. 5. Summary Recommendations West African and other programs faced with HIV-2 patients need locally adapted protocols for testing, treatment, moni- toring, and stock management in order to be eﬀective. With regards to treatment, the delivery of optimal therapy should be a program goal, and although more complicated, it is achievable within a public health framework, with nurse-led clinics, even where infrastructural or staﬃng deﬁcits may exist. For adults with HIV-2 or HIV-1/HIV-2 7 dual infection without access to ART susceptibility testing, optimal antiretroviral therapies for ﬁrst- and second-line treatment are suggested in Tables I(a) and I(b). It is hoped that these recommendations will rapidly become obsolete as other agents and drug classes come into wider use in West Africa, and prospective randomized controlled trials of ART in HIV-2 provide more reliable indications of the suitability of speciﬁc regimens. Acknowledgments T. I. de Silva is supported by a Medical Research Council (UK) Clinical Research Training Fellowship, and S. L. Rowland-Jones is an MRC Research Professor. K. Peterson would like to thank David Katzenstein, Seble Kassaye, and Serge Eholie for several particularly fruitful discussions on sequential ART regimens in West Africa. Most of the authors’ practical experience with HIV-2 management has been based in The Gambia, with the support of the MRC, Flemish interuniversity council (VLIR), and the Global Fund, and to the staﬀ and patients of the Genitourinary Medicine clinic the authors wish to express their appreciation. K. Peterson and S. Jallow contributed equally to the manuscript. References [1] F. 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