The ever-widening spectrum of varicella zoster virus vasculopathy

The short- and long-term risk of stroke after herpes zoster - a nationwide population-based cohort study

BACKGROUND AND OBJECTIVE

Varicella zoster virus (VZV) is known to cause VZV vasculopathy, which may be associated with stroke. A recent study found an increased risk of stroke within one year of herpes zoster. We aimed to investigate the short and long-term effects of herpes zoster on the risk of stroke.

METHODS

Using Danish national registers, we constructed a cohort consisting of all Danish adults ≥18 years old between 1995 and 2008 (n = 4.6 million; person-years of follow-up = 52.9 million). Individual-level information on prescriptions for herpes zoster antiviral treatment and diagnoses of stroke was obtained from national registers. We compared the risk of stroke in persons who had received the specific dosage of acyclovir for herpes zoster with persons who had never received antiviral treatment by Poisson regression.

RESULTS

During follow-up, 2.5% received treatment for herpes zoster and 5.0% were diagnosed with stroke. Individuals who had received medication had a 127% (95% CI 83-182%) increased risk the first two weeks, 17% (CI 9-24%) between two weeks and one year, and 5% (2-9%) after the first year. The increased risk was greatest in the youngest age group (<40). To control for healthcare-seeking behaviour, we conducted parallel analyses investigating the risk of selected fractures after herpes zoster and found no similar increased risks.

CONCLUSIONS

This large nationwide cohort study found an increased risk of stroke after treatment for herpes zoster. Although the short-term risk was particularly high, we cannot rule out the possibility of a small but important long-term risk.

Varicella and Stroke in Children

Varicella zoster virus (VZV) is the only human virus known to replicate in arteries. After the acute infection, the virus persists in a noninfectious latent form in ganglia along the neuraxis, with intermittent periods of reactivation. Both primary and secondary reactivation are associated with stroke in children. These patients, regardless of the chosen treatment, have a high risk of recurrence, particularly those with worsening arterial stenosis. There are no specific therapy protocols for varicella-associated stroke in children, and the use of steroids or antiviral drugs is still controversial. We present a series of 4 children with stroke following varicella infection, with no recurrence and stable vascular stenosis at a mean follow-up of 18 months without steroid treatment. We also analyze possible correlations between anti-protein C, protein S and protein Z autoantibodies, and post-varicella arteriopathy.

Increased risk of stroke after a herpes zoster attack: a population-based follow-up study

BACKGROUND AND PURPOSE

Varicella zoster virus-induced vasculopathy and postherpes zoster attack stroke syndromes have been reported previously; nevertheless, data regarding the exact prevalence and risk of stroke occurring postherpes zoster attack are still lacking. This study aims to investigate the frequency and risk of stroke after a herpes zoster attack using a nationwide, population-based study of a retrospective cohort design. Method- A total of 7760 patients who had received treatment for herpes zoster between 1997 and 2001 were included and matched with 23 280 randomly selected subjects. A 1-year stroke-free survival rate was then estimated using the Kaplan-Meier method. After adjusting for potential confounders, Cox proportional hazard regressions were carried out to compute the adjusted 1-year survival rate.

RESULTS

Of the sampled patients, 439 patients (1.41%) developed strokes within the 1-year follow-up period, that is, 133 individuals (1.71% of the patients with herpes zoster) from the study cohort and 306 individuals (1.31% of patients in the comparison cohort) from the comparison cohort. The log rank test indicated that patients with herpes zoster had significantly lower 1-year stroke-free survival rates than the control (P<0.001). The adjusted hazard ratios of stroke after herpes zoster and herpes zoster ophthalmicus during the 1-year follow-up period were 1.31 and 4.28, respectively.

CONCLUSIONS

The risk for stroke increased after a zoster attack. Although varicella zoster virus vasculopathy is a well-documented complication that may induce a stroke postherpes zoster attack, it does not fully account for the unexpectedly high risk of stroke in these patients.