Infection with two strains of the same HIV-1 subtype can lead to very rapid disease progression, US researchers warn today in the February 21st edition of The Lancet.
The researchers, from the University of Washington, Seattle, Johns Hopkins University School of Medicine and the universities of Natal and Cape Town in South Africa, identified five dually infected patients among their cohorts of individuals with known seroconversion dates for HIV.
Four had dual infections with two variants of HIV-1 subtype B (predominant in the USA) and one had dual infection with two variants of HIV-1 subtype C (common in southern Africa). Four were found to be infected with two variants of HIV-1 when their HIV infection was first identified and one became superinfected with another HIV-1 variant 1.3 years after seroconversion.
Their disease course was compared with disease progression in 34 monoinfected seroconverters from cohorts in the United States (men) and South Africa (female sex workers).
Dually infected individuals had a threefold higher risk of disease progression during the follow-up period. The average time from seroconversion to development of an AIDS-defining illness or death was less than 3.4 years, and the average time from seroconversion to a CD4 cell count below 200 cells/mm3 was 3.1 years. In comparison, other cohorts (in which the vast majority are likely to have been monoinfected) have shown an interval of between eight and ten years between seroconversion and the development of AIDS, and only 2-3% of people are likely to develop AIDS within two years of seroconversion.
Although CD4 cell decline was rapid in these patients, the average viral load values in the first year after seroconversion were not significantly higher than in the monoinfected control group (5.0 log10 copies/ml versus 4.5log10 copies/ml).
The authors suggest that host factors that increase the risk of disease progression after a virus is acquired could also increase susceptibility to infection in the first place.
They also warn: “In a time of increasing unsafe sexual practices in some groups, our data indicate a potential hazard of acquiring viruses from separate sources.”
Further information on this website
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Reference
Gottlieb GS et al. Dual HIV-1 infection associated with rapid disease progression. The Lancet 362: 619-622, 2004.