The incidence of herpes zoster increased the risk for stroke within the first 6 months of infection, according to researchers from the United Kingdom. However, antiviral therapy may decrease that risk.
"This study has established an increased stroke rate within 6 months following acute herpes zoster," Sinéad Langan, MD, PhD, told Infectious Disease News. "The study findings have implications for zoster vaccination programs, as vaccination may reduce stroke risk following zoster."
Langan and colleagues at the London School of Hygiene and Tropical Medicine identified 6,584 patients in the United Kingdom who had a first-ever diagnosis of herpes zoster and stroke between 1987 and 2012. The researchers compared the incidence of stroke after infection with herpes zoster with other periods in which patients were not recently exposed to the infection. They also examined patient health records to determine whether antiviral therapy had been delivered.
The incidence of stroke increased significantly within the first 4 weeks of infection with herpes zoster compared with the rate at baseline (incidence ratio [IR]=1.63; 95% CI, 1.32-2.02), and the stroke risk slowly diminished during the next 6 months (weeks 5-12: IR=1.42; 95% CI, 1.21-1.68; weeks 13-26: IR=1.23; 95% CI, 1.07-1.42).
In particular, patients with herpes zoster ophthalmicus faced more than a threefold transient increased risk for stroke 5 to 12 weeks after infection (IR=3.38; 95% CI, 2.18-5.24).
According to the researchers, 55% of patients with herpes zoster were treated with oral antiviral therapy, and the stroke risk for these patients was significantly lower vs. those who received no antivirals (weeks 1-4: IR=2.14; 95% CI, 1.62-2.84), suggesting a protective effect of antiviral treatment.
"The low antiviral prescribing rate needs to be improved as our data suggest that antiviral therapy may lead to a reduced stroke risk following zoster," Langan said.
Infection with herpes zoster affects approximately 1 million people each year in the United States, and approximately 90,000 adults older than 60 years are infected annually in the United Kingdom, the researchers noted.
Langan and colleagues said the association between herpes zoster and stroke can be explained by the development of varicella-zoster virus vasculopathy, which could trigger ischemic or hemorrhagic stroke.
In an accompanying editorial, Maria A. Nagel, MD, and Donald H. Gilden, MD, of the University of Colorado School of Medicine, wrote that the findings are supported by previous studies from the United Kingdom, Taiwan and Denmark.
However, “the current study is the first to show that the increased risk of stroke after zoster can be reduced with antiviral treatment,” they wrote. – John Schoen
For more information:
Langan SM. Clin Infect Dis. 2014;doi:10.1093/cid/ciu098.
Nagel M. Clin Infect Dis. 2014;doi:10.1093/cid/ciu099.
Disclosure: The researchers report no relevant financial disclosures.