Human Immunodeficiency Virus (HIV) 2 Superinfection in a Patient Receiving Antiretroviral Therapy With Longstanding HIV-1 Viral Load Suppression.

Dual human immunodeficiency virus (HIV) 1 and HIV-2 superinfections are rare but challenging. A HIV-1-infected patient receiving effective antiretroviral therapy was investigated for a severe CD4+ cell count decline. HIV-2 superinfection was diagnosed and genotypic test revealed mutations conferring resistance to most drug class, limiting options for treatment.