The Epstein-Barr virus (EBV) is the likely leading cause of multiple sclerosis (MS). (Bjornevik et al., 2022) Debates continue regarding the potential benefit of antiviral treatment for EBV after the onset of MS. Tenofovir prodrugs, used in highly active antiretroviral therapy (HAART) for HIV treatment, have shown potent inhibition of EBV in B-cells in vitro. (Drosu et al., 2020) Intriguingly, several case reports describe people with MS on HAART containing tenofovir with no evidence of MS disease activity, (Chalkley and Berger, 2014; Delgado et al., 2014; Labella et al., 2021; Maulucci et al., 2015; Torkildsen et al., 2020; Skarlis et al., 2018) and epidemiological studies have reported a lower incidence of MS in patients with HIV. (Gold et al., 2015; Nexø et al., 2013) Although these observations could be due to immunosuppression from HIV, patients on HAART often maintain undetectable viral loads and normal CD4 T cell counts. This raises the question of whether HIV treatment may be reducing MS disease activity by inadvertently treating EBV. Here, we present the case of an MS patient with significant brain and spinal cord disease burden at diagnosis who has remained clinically and radiologically stable for more than nine years while on a HAART regimen containing tenofovir and in the extended absence of disease-modifying therapies (DMTs) for MS.