This common vaccine was just found to reduce MI and stroke risk by 26%—there's just one big problem
Key Takeaways
Industry Buzz
“For the first time, this has allowed us to examine the association between shingles vaccination and 18 different types of cardiovascular disease. We were able to account for various other health conditions, lifestyle factors and socioeconomic status, making our findings more robust.” — Dong Keon Yon, MD, assistant professor at Kyung Hee University College of Medicine
Recent research has unveiled that the shingles vaccine, Zostavax, may offer protective benefits beyond preventing infection caused by the varicella-zoster virus.
New evidence suggests it could reduce the risks of cardiovascular events—by 26% over 8 years—while also reducing dementia risk. The trouble is, Zostavax hasn't been available in the US since 2020. []
Cardiovascular benefits: Zostavax's legacy
A large-scale South Korean study, published in the European Heart Journal, analyzed data from over 1.2 million adults aged 50 and above. []
The findings indicated that recipients of the live-attenuated zoster vaccine, Zostavax, experienced a 23% reduction in overall cardiovascular events, including a 26% decrease in major incidents such as stroke, heart attack, and heart failure.
These protective effects were most pronounced within the first two to three years post-vaccination but persisted for up to eight years. Notably, the benefits were especially significant among men, individuals under 60, and those with unhealthy lifestyles.
The proposed mechanism involves the prevention of shingles-associated inflammation and vascular damage, which can contribute to cardiovascular complications.
Related: The elusive staph vaccine: A study unravels the challenges faced by the medical communityTransition to Shingrix: A modern alternative
Despite Zostavax's potential cardiovascular benefits, it was discontinued in the US in 2020 due to waning effectiveness over time and limited protection for older adults and immunocompromised individuals. []
It was replaced by Shingrix, a recombinant subunit vaccine approved by the FDA in 2017, which demonstrates over 90% efficacy against shingles and postherpetic neuralgia. []
While Shingrix's effectiveness in preventing shingles is well-established, its impact on cardiovascular outcomes remains under investigation.
Ongoing studies aim to determine whether Shingrix offers similar cardioprotective effects as observed with Zostavax. []
Neurological implications: Dementia risk reduction
While scientists can't yet confirm that US patients can reap similar cardio benefits from Shingrix, there's some good news: It was recently found to have significant impact on dementia risk.
A study published in Nature Medicine found that recipients of the recombinant shingles vaccine had a 17% increase in dementia-free time over six years compared to those who received the live vaccine. []
Additionally, a study in Wales observed a 20% relative reduction in dementia diagnoses over seven years among vaccinated individuals. []
These findings imply that Shingrix may offer superior protection against cognitive decline compared to its predecessor.
Zostavax lawsuits and next steps
Merck has resolved over 1,000 lawsuits related to its shingles vaccine, Zostavax, following voluntary dismissals filed by plaintiffs. [] The US Court of Appeals for the Third Circuit upheld the dismissal of these cases, which alleged that Zostavax caused patients to develop shingles.
Merck continues to face additional lawsuits, with some plaintiffs alleging that Zostavax caused various injuries beyond shingles, including hearing loss.
The legal challenges surrounding Zostavax highlight the importance of robust clinical evidence in vaccine-related litigation. Healthcare professionals should remain informed about the evolving legal landscape concerning vaccine safety and efficacy, as these cases may influence future regulatory and clinical practices.
Related: A cardiologist’s top-3 supplements for heart health