INTRODUCTION:
Herpes zoster (HZ) reactivation is characterized as a vascular rash of unilateral distribution that can also cause complications such as post-herpetic neuralgia, ophthalmic zoster, and other neurological diseases. Emerging epidemiological and clinical data recognizes an association between HZ and subsequent acute strokes and myocardial infarction (MI).

DISCUSSION:
Wu et al.1Wu, P. H., Chuang, Y. S., & Lin, Y. T. (2019). Does herpes zoster increase the risk of stroke and myocardial infarction? A comprehensive review. Journal of Clinical Medicine, 8(4), 547. https://doi.org/10.3390/jcm8040547 reviewed published articles to explore the possible association between HZ and cerebrovascular and cardiac events. Lesions during an HZ episode are mostly in the thoracic regions (>50%) but is also possible in the ophthalmic, cervical, and lumbosacral regions. Herpes zoster ophthalmicus (HZO) involves the ophthalmic branch of the trigeminal nerve and can occur in approximately 10 to 20% of HZ cases. Reactivated varicella-zoster virus (VZV) can introduce complications of post-herpetic neuralgia, myelitis, meningoencephalitis, and VZV vasculopathy. This report looks at several papers that show an association between vascular diseases and VZV reactivation. Their review was to determine whether there is a significant correlation between HZ, strokes, and MI. They examined electronic databases to identify studies that included the following terms: HZ, shingles, HZO, stroke, transient ischemic attack (TIA), a composite of stroke and TIA, and myocardial infarction (MI). Fifteen studies examined the association between unspecified HZ types and the following: non-specific stroke, ischemic stroke, hemorrhagic stroke, TIA, a composite of stroke and TIA, myocardial infarction, acute coronary syndromes (MI and unstable angina), and incident coronary artery disease including angina and MI. There were eight studies regarding HZO and cardiovascular disease (CVD), five studies on non-specified stroke, and studies with ischemic stroke, hemorrhagic stroke, and MI. The follow-up times ranged from one week to 24 years. They used six meta-analysis studies to investigate the correlation between HZ and cerebrovascular risk. Examining these studies showed that individuals exposed to HZ or HZ ophthalmicus had a 1.3 to 4-fold increased risk of cerebrovascular events. Higher risks were noted among younger patients (age <40) within one year after an HZ episode. The elevated risk of cardiovascular events diminished gradually according to age and length of time after an HZ episode. VZV infection of the cerebral arteries with subsequent inflammation leads to vascular remodeling and thickened intima that contributes to vascular occlusion in patients with VZV vasculopathy.

CONCLUSION:
Epidemiological studies and the pathology of VZV vasculopathy indicate that HZ is a significant risk factor for stroke within one year after an HZ episode. Limited reports indicated that antiviral treatment reduces stroke risk. The authors noted that it was difficult to confirm the relationship between the shingles vaccine and cerebrovascular events because of the small sample size. The authors indicated a need for more studies to determine the effect of optimal antiviral treatment and shingles vaccination on reducing cerebrovascular and CVD burden, especially for patients with pre-existing high CVD risk. An earlier review by Kang et al.2Kang, J. H., Ho, J. D., Chen, Y. H., and Lin, H. C. (2009). Increased risk of stroke after a herpes zoster attack. A population-based follow-up study. Stroke, 40(11), 3443-3448. https://doi.org/10.1161/strokeaha.109.562017 of data from 439 patients came to the same conclusion in linking increased stroke risk after an HZ event. In this regard, common sense would suggest that reducing the occurrence of a shingles infection with a vaccine, such as Shingrix™, would lessen the chances of either strokes or MIs from occurring.

By David Kilpatrick, PhD and Abbas Vafai, PhD

MKTG 1048 Rev A