Incidence and risk factors of herpes zoster in human immunodeficiency virus-positive patients initiating combination antiretroviral therapy in Taiwan.

Background/purpose: To obtain current epidemiological data for better vaccination policies, this study aimed to assess the incidence and risk factors of herpes zoster in human immunodeficiency virus (HIV)-positive patients initiating combination antiretroviral therapy (cART) in Taiwan.

Methods: Between June, 2012 and May, 2015, we prospectively identified zoster cases in HIV-positive patients initiating cART. Clinical information was collected on demographics, prior zoster, plasma HIV-1 RNA load (PVL), and CD4 count at baseline and during follow up. A case-control study by 1:2 matched pairs was used to identify the risk factors for zoster development.

Results: During the 3-year study period, 826 patients with a mean age of 32.9 years were included, and 7.7% had prior zoster. The mean baseline CD4 count and PVL were 286 cells/μL and 4.90 log copies/mL, respectively. Fifty-four (6.5%) patients developed zoster after initiation of cART, with 43 episodes (79.6%) occurring within 1 year of cART initiation, which corresponded to an overall incidence rate of 3.61/100 person-years. The multivariate analysis revealed that prior zoster (adjusted odds ratio = 3.143; 95% confidence interval, 1.385-7.133) and baseline CD4 count < 200 cells/μL (adjusted odds ratio = 2.034; 95% confidence interval, 1.020-4.057) were independent risk factors for zoster in HIV-positive patients initiating cART. In case-control study, prior zoster and baseline PVL > 5 log copies/mL were risk factors for zoster development after cART initiation in multivariate analysis.

Conclusions: Herpes zoster occurred in 6.5% of HIV-positive Taiwanese patients after initiation of cART, which was associated with prior zoster and baseline CD4 count < 200 cells/μL or baseline PVL > 5 log copies/mL.