Incidence of herpes zoster in HIV-infected adults in the combined antiretroviral therapy era: results from the FHDH-ANRS CO4 cohort.

Background: Recent studies have shown a decrease in the incidence of herpes zoster (HZ) among human immunodeficiency virus (HIV)-infected patients since the combined antiretroviral therapy (cART) era, but more data are needed on a possible increase in the risk early after cART initiation.

Methods: We studied HZ incidence and risk factors among patients followed in the French Hospital Database on HIV (FHDH) between 1992 and 2011. Standardized incidence ratios (SIRs) were used for comparison with the general population between 2005 and 2008. The risk of HZ following cART initiation (0-5 and ≥6 months) was studied with Poisson regression models.

Results: A total of 7167 cases of incident HZ were diagnosed among 91 044 individuals (583 125 person-years [PY]). The incidence declined significantly, from 2955 per 100 000 PY in 1992-1996 to 628 per 100 000 PY in 2009-2011. This decline was mainly explained by cART (relative risk [RR], 0.60; 95% confidence interval {CI}, .57-.64). The risk of HZ was associated with low CD4 cell counts, high HIV RNA levels, low CD4/CD8 ratios, and prior AIDS. Compared to the general population, the risk of HZ was higher in HIV-infected patients (overall SIR, 2.7; 95% CI, 2.6-2.9), particularly those aged 15-44 years (SIR, 4-6). In ART-naive patients, a moderate increase in the HZ risk was observed during the first 6 months of cART, with a peak at 3 months (RR, 1.47; 95% CI, 1.26-1.73), a finding that disappeared after adjustment for the current CD4 cell count (RR, 1.03; 95% CI, .81-1.32).

Conclusions: The risk of HZ has declined markedly among HIV-infected patients in the cART era, but remains 3 times higher than in the general population. The risk increases moderately during the first 6 months of cART.