Treating shingles after the fact with antivirals and vaccine doesn’t reduce the elevated risk of stroke that persists for months afterward, according to a recent conference presentation.
Preliminary research was presented at the American Stroke Association’s International Stroke Conference 2019 in Honolulu, Hawaii. In this study, investigators from the CDC reviewed the cases of more than 35,000 Medicare fee-for-service beneficiaries who had been diagnosed with herpes zoster (HZ) and acute ischemic stroke (AIS) between 2007 and 2015.
The question the investigators sought to answer was whether having the zoster vaccine live—marketed as Zostavax—as a treatment, antiviral therapy, or both, after infection with shingles would affect stroke risk.
Medicare beneficiaries were divided into four groups:
• no vaccination and no antiviral treatment;
• vaccination only;
• antiviral treatment only; and
• both vaccination and antiviral treatment.
In most of the cases reviewed (60.9%) neither vaccination nor antiviral treatment had been provided to shingles patients, although twice as many (22.2%) received antivirals versus vaccine (11.8%).
Incidence rate ratios at 0 to 14, 15 to 30, 31 to 90, and 91 to 180 days following HZ were 1.48 (95% CI, 1.37-1.59), 1.31 (95% CI, 1.21-1.42), 1.18 (95% CI, 1.12-1.24), and 1.07 (95% CI, 1.03-1.13), respectively.
However, the researchers reported neither HZ vaccination nor antiviral treatment—nor a combination—appeared to have any effect on stroke incidence. Furthermore, they pointed out that the pattern of association between HZ and risk for AIS was consistent across age groups (age 66 to 74 years, age 75 to 84 years, and age 85 years and older), as well as sex and race (non-Hispanic white, non-Hispanic black, Hispanic, and other).
“Risk of AIS increased significantly following HZ, and this increased risk didn’t appear to be modified by HZ vaccination and antiviral treatment following HZ,” the study authors concluded. “Primary prevention of HZ by HZ vaccination might be the most effective approach to prevent HZ-associated AIS.”
The study found that stroke incidence increased by 61% within 14 days after shingles onset and remained elevated 6 months afterward, although it diminished over time.
In this study, researchers examined the effect of the Zostavax shingles vaccine because Medicare data were not yet available for the Shingrix recombinant zoster vaccine. The presentation pointed out that Zostavax efficacy declines over time, with protection from shingles lasting only about 5 years.
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