HIV-2 Just as Deadly as HIV-1, but at a Slower Rate

A recent study compared the time to AIDS and mortality and the CD4 T-cell dynamics between HIV-1 and HIV-2, finding that both groups have a high probability of developing and dying from AIDS without antiretroviral treatment (ART).

HIV-1 is known to play a more significant role in the HIV pandemic than HIV-2, therefore there is minimal research involving estimates of time to AIDS and mortality among those with HIV-2.

“Both viruses share transmission routes, cellular targets, and a range of opportunistic infections. HIV-2 infection is, however, characterized by lower numbers of transmission, longer asymptomatic stages, slower declines in CD4 cell counts, and lower mortality. Without ART, most individuals develop AIDS and die within 3—13 years after HIV-1 infection,” noted the authors. “Corresponding estimates among those with HIV-2 infection have not been presented, mainly due to a paucity of data with both estimated date of HIV-2 infection and long follow-up.”

The study included all police officers with regular employment from police stations in urban and rural areas of Guinea-Bissau since February 1990 and continued to include new participants until September 2009. The researchers followed up with the HIV-1 positive and HIV-2 positive individuals until September 2013.

Blood samples were collected at enrollment and at the scheduled follow-up visits, while longitudinal data from individuals infected with HIV-1 and HIV-2 were analyzed according to time to AIDS, death, and T-cell dynamics. Data were also collected from 2984 HIV-uninfected individuals in the same population in order to determine the effect of natural mortality on HIV-related mortality.

The results revealed that 872 participants tested HIV positive, with 408 infected with HIV-1, and 464 infected with HIV-2. The median time from HIV infection to development of AIDS was 6.2 years for HIV-1 and 14.3 years for HIV-2, while the median survival time after HIV was 8.2 years for HIV-1 and 15.6 years for HIV-2. The authors noted that individuals who were infected with HIV-1 or HIV-2 before enrollment demonstrated similar results.

The average CD4 percentages were found to be higher in those with HIV-2 than those with HIV-1 during early infection but declined at a lower rate per year. Also, those with HIV-2 developed clinical AIDS at higher mean CD4 percentages than those with HIV-1, according to the study.

“Our results support the recent WHO ART guidelines of early treatment initiation for all HIV-infected individuals, not only those infected by HIV-1. Moreover, clinical trial data are urgently needed to establish the evidence base for optimal usage of ART in HIV-2 infection,” concluded the authors.

Reference:

Esbjörnsson J, Månsson F, Kvist A, et al. Long-term follow-up of HIV-2-related AIDS and mortality in Guinea-Bissau: a prospective open cohort study [published November 1, 2018]. Lancet HIV. doi: 10.1016/S2352-3018(18)30254-6.