Which of the following is more virulent?

Explanation

HIV-2 is less virulent, has a slower disease progression, and is mostly confined to West Africa, with limited global spread. HIV-1(a), a subtype of HIV-1, is more virulent than HIV-2 and contributes significantly to worldwide infections, showing faster progression. HIV-2(a), a subtype of HIV-2, remains less virulent and follows the same pattern of slower transmission and disease development as HIV-2 in general. HIV-1, overall, is the most virulent type, responsible for the majority of HIV infections worldwide, with rapid progression to AIDS if untreated. Therefore, HIV-1 is considered more virulent than HIV-2.