Dual HIV infection: epidemiology, clinical significance, and diagnosis
This literature review is devoted to the problem of dual HIV infection, i.e. coexistence of at least two HIV strains in one patient. Dual HIV infection can be caused by a combination of HIV-1 and HIV-2 (intertype infection), different groups of viruses (intergroup infection), different subtypes of viruses (intersubtype infection), or different variants of viruses of the same subtype (intrasubtype infection). Dual infection can occur simultaneously with the first infection or after some time (coinfection) or after the development of the immune response to the initial viral strain (superinfection). This article also covers the impact of dual HIV infection on the global epidemics of HIV, its clinical course, and diagnostics of dual infection. Dual infection, which is found in some vulnerable groups with a frequency of more than 14%, promotes the emergence of new recombinant forms and facilitates the selection of new viral variants (including drug-resistant ones). High prevalence of recombinant HIV-1 strains in the Russian Federation indicates that studies on dual HIV infection are highly relevant in our country.