Buffalo, NY—A few studies have identified stroke as a risk after varicella-zoster virus (VZV) infection, but whether zoster vaccination can play a protective role has been unclear.

Researchers from the Veteran Affairs Western New York Healthcare System in Buffalo and the University of Buffalo sought to determine the risk of stroke 30 days following zoster infection and to evaluate the impact of zoster vaccinations on the risk of stroke in VZV-infected patients.

To do so, the retrospective, case-control study conducted from January 2010 to January 2020 used nationwide patient data retrieved from the Veterans Affairs’ (VA) Corporate Data Warehouse. The study included information on nearly 72,000 patients with a history of zoster infection at a VA facility. The results were published in Clinical Infectious Diseases.

The study found that zoster patients had a 1.9 times increased likelihood of developing a stroke within 30 days following infection (OR: 1.93 [95% CI: 1.57-2.4] P <.0001). On the other hand, a decreased risk of stroke was seen in patients who received the recombinant zoster vaccine (OR 0.57 [95% CI: 0.46-0.72] P <.0001) or the live zoster vaccine (OR 0.77 [95% CI: 0.65-0.91] P = .002), which is no longer available.

“Patients had a significantly higher risk of stroke within the first month following recent herpes zoster infection,” the researchers advised. “Receipt of at least one zoster vaccination was found to mitigate this increased risk. Vaccination may therefore be viewed as a protective tool against the risk of neurologic post-infection sequelae.”

A recent international study led by South African researchers pointed out that infections are an underappreciated cause of stroke, especially in young and immunocompromised individuals.

“Varicella zoster virus (VZV) reactivation, particularly ophthalmic zoster, has been linked to increased risk of stroke, but diagnosing VZV-associated cerebral vasculopathy is challenging as neither a recent zoster rash, nor detectable levels of VZV DNA are universally present at stroke presentation,” the researchers wrote in the Journal of Medical Virology. “Detection of VZV IgG [immunoglobulin G] in cerebrospinal fluid (CSF-VZVG) presents a promising alternative, but requires evaluation of individual blood-CSF dynamics, particularly in the setting of chronic inflammatory states such as HIV infection. Consequently, its use has not been broadly adopted as simple diagnostic algorithms are not available.”

The recent study focuses on young adults presenting with acute stroke. The study team employed an algorithm that includes testing for both VZV nucleic acids and CSF-VZVG, which was corrected for blood-CSF barrier dynamics and poly-specific immune activation.

The results indicated that evidence of central nervous system reactivation of VZV was demonstrated by:

• 13 of 35 (37%), including seven with a positive CSF VZV PCR, young HIV-infected adults presenting with stroke.
• Three of 34 (9%) young HIV-uninfected adults presenting with stroke.
• One of 18 (6%) HIV-infected nonstroke controls.

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