Cardoso, MargaridaVasconcelos, JoanaBaptista, TeresaDiogo, IsabelGonçalves, FátimaMansinho, KamalGomes, Perpétua2025-09-242025-09-242021-10Cardoso, M., Vasconcelos, J., Baptista, T. et al. Management of HIV-2 resistance to antiretroviral therapy in a HIV-1/HIV-2/HBV co-infected patient. AIDS Res Ther 18, 69 (2021). https://doi.org/10.1186/s12981-021-00394-41742-6405http://hdl.handle.net/10400.26/58821Background: The current standard of care is to start antiretroviral therapy in all patients diagnosed with HIV-1, as for HIV-2 current DHHS guideline suggests ART for HIV-2 as soon as diagnosis is established, although this practice is not universal, for instance, in Portugal there are specific criteria to start treatment. Case presentation: We present a case of a man, chronically infected with HIV-1, HIV-2 and hepatitis B virus who developed resistance to HIV-2 while maintaining HIV-1 under control. 6 years after starting antiretroviral therapy he had his first virologic failure. We performed HIV-2 resistance tests that revealed high-grade resistance to all nucleoside reverse-transcriptase inhibitors except tenofovir and to all protease inhibitors except darunavir. After a decade of permanent poor adherence to therapy he developed resistance to both tenofovir and darunavir. We put together a new regiment with tenofovir alafenamide + emtricitabine + dolutegravir + maraviroc and nowadays he is with undetectable HIV-1 and HIV-2 viral loads. Conclusions: This shows the importance of having access to HIV-2 viral load determination and HIV-2 resistance testing.engHIV-2HIV-1ResistanceMutationCoinfectionAntiretroviral therapycontribution to journal10.1186/s12981-021-00394-4