HIV-1 subtype in Scotland: the establishment of a national surveillance system

Historically, subtype B viruses in men who have sex with men (MSM) and injecting drug users (IDU) dominated the HIV epidemic in the United Kingdom, whereas non-B heterosexual infections dominate globally. Heterosexual contact is now the most common route of transmission in the United Kingdom. Here we monitor HIV subtype in Scotland, and link it to origin of infection. HIV-1 sequence was generated from new diagnoses and the subtype thus obtained linked with demographic data. Virus was subtyped from 80% (137/171) of all new diagnoses in Scotland. Of 58 individuals infected by heterosexual contact, 74% (43) harboured non-B viruses, contrasting with 7% (5/68) of those infected by IDU or MSM. Eighty-four per cent of non-Bs (46/55) were probably acquired outside the United Kingdom, but nine individuals probably acquired their non-B infection in the United Kingdom. Non-B subtypes of HIV-1 predominate in recently diagnosed, heterosexually acquired infections in Scotland and are present in all risk groups, even those with no exposure outside the United Kingdom.