Shingles Vaccine Could Reduce Stroke Risk
FEBRUARY 12, 2020
Quanhe Yang, PhD
Presented at the American Stroke Association’s International Stroke Conference (ISC), the results indicate the Zoster Vaccine Live not only reduced the risk for shingles, but also reduced stroke risk by 16% in older adults.
"Our study results may encourage people ages 50 and older to follow the recommendation and get vaccinated against shingles,” said Quanhe Yang, PhD, lead investigator and senior scientist at the CDC in Atlanta, GA, in a statement. “You are reducing the risk of shingles, and at the same time you may be reducing your risk of stroke."
While previous research has linked herpes zoster to an increased risk of stroke in older patients, no studies had established a definitive link between the Zoster Vaccine Live and the risk of stroke in this population group. To perform such as assessment, Yang and a team of CDC colleagues performed a retrospective analysis using the Medicare health records of more than 1.3 million Medicare fee-for-service beneficiaries.
For inclusion in the analysis, patients were required to be 66 years of age or older, have no stroke history, and must have received the Zoster Vaccine Live between 2008-2014. A total of 1,382,051 individuals were identified for inclusion and investigators proceeded to match this cohort with 1,382,051 controls to control for age, gender, race, medications, and comorbidities.
Cox proportional hazards models were used to examine the association between the vaccine and a composite endpoint of fatal and nonfatal incident stroke outcomes. Additional analyses were performed examining the effectiveness of the vaccine and stroke reduction stratified by different age groups.
During follow-up, which had a median length of 3.9 years, a total of 42,267 stroke events occurred over 5,890,113 person-years among those who received the vaccine. Of the 42,267 events, 33,510 were acute ischemic strokes and 4318 were hemorrhagic strokes.
Among matched controls, 48,139 total stroke events occurred over 5,693,943 person-years. Of the 48,139 events, 39,334 were acute ischemic strokes and 4713 were hemorrhagic strokes.
When comparing the groups, lower incidence rates per 1000 person-years were observed among those who received the Zoster Live Vaccine than those who did not for all stroke events (7.18 vs 8.45), acute ischemic stroke (5.40 vs 6.53), and for hemorrhagic stroke (0.73 vs 0.82; P <.001 for difference). Results of the Cox proportional hazards models indicated receiving the vaccine decreased risk of stroke by 16%, risk of ischemic stroke by approximately 18%, and risk of hemorrhagic stroke by 12%.
Of note, results indicate the beneficial impact on stroke risk appeared to be greater in patients 79 years of age and younger than in the older patients examined. Additionally, investigators pointed out the study examined a time period when the Zoster Vaccine Live was the only shingles vaccine available.
This study, “Herpes Zoster Vaccine Live And Risk For Stroke Among Medicare Beneficiaries: Population Based Matched Cohort Study,” was presented at ISC 2020 in Los Angeles, CA.