Treating shingles after it appears doesn't reduce increased stroke risk

by American Heart Association

Stroke risk increased significantly in the days, weeks and months after shingles appeared, despite use of the shingles vaccine and antiviral therapy to treat it, according to preliminary research to be presented in Honolulu at the American Stroke Association's International Stroke Conference 2019, a world premier meeting for researchers and clinicians dedicated to the science and treatment of cerebrovascular disease.

12 feb 2019--Centers for Disease Control and Prevention (CDC) researchers studied more than 35,000 Medicare fee-for-service beneficiaries who had been diagnosed with shingles, also known as herpes zoster, and acute ischemic stroke between 2007 and 2015. They analyzed whether having the shingles vaccine, Zostavax, as a treatment, antiviral therapy or both after shingles would impact patients' stroke risk. They found that stroke incidence jumped by 61 percent within 14 days after shingles onset. The increased stroke risk remained elevated six months after shingles but diminished with time.

Researchers didn't find any evidence that having the vaccine or taking antiviral therapy once shingles appeared helped to reduce the increased stroke risk. But the researchers suggest having the shingles vaccine might be the most effective way to prevent shingles-associated stroke risk.

Shingles is an often painful rash caused by the virus that causes chicken pox. Almost one in three people in the United State will develop shingles in their lifetime, according to CDC. The American Heart Association recommends adults over age 50 get the shingles vaccine. The new vaccine, Shingrix, approved by FDA in 2017 has shown to be more than 90 percent effective at preventing shingles. In this study, researchers examined the effect of the Zostavax shingles vaccine because Medicare data was not yet available for the Shingrix shingles vaccine. Zostavax efficacy declines over time and protection from shingles only lasts about 5 years with Zostavax.

Provided by American Heart Association

Does herpes cause Alzheimer's?

What causes Alzheimer's disease? The answer could be right under our noses, says leading expert Professor Ruth Itzhaki. Her latest paper presents a lifetime of research evidence that the herpes virus responsible for cold sores can also cause Alzheimer's—and new data which show antiviral drugs drastically reduce risk of senile dementia in patients with severe herpes infections. The review in Frontiers in Ageing Neuroscience raises the tantalizing prospect of a simple, effective preventive treatment for one of humanity's costliest disorders.

The HSV1 theory of Alzheimer's disease

19 oct 2018--Herpes viruses are the dreaded 'gift that keeps on giving'. They remain lifelong in our neurons and immune cells, reactivating and resurfacing in characteristic blisters when we're run down by stress or illness. Most people are infected by Herpes Simplex Virus 1 (HSV1) by the time they reach old age.
But what happens to infected neurons in our brain during this reactivation?
"HSV1 could account for 50% or more of Alzheimer's disease cases," says Professor Itzhaki, who has spent over 25 years at the University of Manchester investigating a potential link.
HSV1 is better known as the cause of cold sores. Itzhaki has shown previously that cold sores occur more frequently in carriers of APOE-ε4—a gene variant that confers increased risk of Alzheimer's.
"Our theory is that in APOE-ε4 carriers, reactivation is more frequent or more harmful in HSV1-infected brain cells, which as a result accumulate damage that culminates in development of Alzheimer's."

Proving the theory

Few countries collect the population data required to test this theory—for example, to find out whether antiviral treatments reduce dementia risk.
In Taiwan however, researchers have done just that. There, 99.9% of the population is enrolled in a National Health Insurance Research Database, which is being extensively mined for information on microbial infections and disease. In 2017-2018 three studies were published describing Taiwanese data on the development of senile dementia—of which Alzheimer's is the main cause—and the treatment of patients with marked overt signs of infection with HSV or varicella zoster virus (VZV, the chickenpox virus).
"The striking results include evidence that the risk of senile dementia is much greater in those who are infected with HSV, and that anti-herpes antiviral treatment causes a dramatic decrease in number of those subjects severely affected by HSV1 who later develop dementia."
Previous findings from Itzhaki's own research group provide a mechanistic link which supports these epidemiological findings. They found that HSV1 causes protein deposits characteristic of Alzheimer's: 'plaques' between neurons, and 'tangles' inside of them.
"Viral DNA is located very specifically within plaques in postmortem brain tissue from Alzheimer's sufferers. The main proteins of both plaques and tangles accumulate also in HSV1-infected cell cultures—and antiviral drugs can prevent this."

Towards a cure

"It should be stressed that the results of these Taiwanese studies apply only to severe HSV1 (or VZV) infections, which are rare," admits Itzhaki. "Ideally, we would study dementia rates amongst people who have suffered mild HSV1 infection, including herpes labialis (cold sores) or mild genital herpes, but these are far less likely to be documented."
Although further work is needed to confirm and define a causal link between HSV1 infection and Alzheimer's, Itzhaki is enthusiastic about the treatment prospects.
"Considering that over 150 publications strongly support an HSV1 role in Alzheimer's, these Taiwan findings greatly justify usage of antiherpes antivirals—which are safe and well-tolerated—to treat Alzheimer's disease.
"They also incentivize development of an HSV1 vaccine, which would likely be the most effective treatment."
This echoes the growing use worldwide of human papillomavirus (HPV) vaccination to prevent cervical cancer—another virus-disease link which emerged in a similar process of research.

More information: Ruth F. Itzhaki, Corroboration of a Major Role for Herpes Simplex Virus Type 1 in Alzheimer's Disease, Frontiers in Aging Neuroscience (2018). DOI: 10.3389/fnagi.2018.00324


Provided by Frontiers

Herpes zoster is linked to increased rates of both stroke and myocardial infarction

Herpes zoster (also called "shingles") is linked to a transient increased risk of stroke and myocardial infarction (MI) in the months following initial zoster diagnosis, according to a study published by Caroline Minassian and colleagues from the London School of Hygiene and Tropical Medicine, UK, published in this week's PLOS Medicine.

19 dec 2015--The researchers identified 42,954 Medicare beneficiaries aged ?65 years who had had a herpes zoster diagnosis and an ischemic stroke and 24,237 beneficiaries who had had a herpes zoster diagnosis and an MI during a 5-year period. They then calculated age-adjusted incidence ratios for stroke and MI during pre-defined periods up to 12 months after a diagnosis of zoster relative to time periods when the patient did not have recent zoster (the baseline period). Compared to the baseline period, there was a 2.4-fold increased rate of ischemic stroke and a 1.7-fold increased rate of MI in the first week after herpes zoster. The increased rate of acute cardiovascular events reduced gradually over the 6 months following herpes zoster. There was no evidence that MI or ischemic stroke incidence ratios varied between individuals who had been vaccinated against zoster and those who had not been vaccinated.
While the researchers used a self-controlled case series design that controls for fixed confounders, residual confounding by time-varying factors such as major life events or stress may limit the accuracy of the findings. Furthermore, only a few participants in the study were vaccinated, which limits the study's power to detect an effect of vaccination.
The authors say "These findings enhance our understanding of the temporality and magnitude of the association between zoster and acute cardiovascular events."

More information: Minassian C, Thomas SL, Smeeth L, Douglas I, Brauer R, Langan SM (2015) Acute Cardiovascular Events after Herpes Zoster: A Self-Controlled Case Series Analysis in Vaccinated and Unvaccinated Older Residents of the United States. PLoS Med 12(12): e1001919. DOI: 10.1371/journal.pmed.1001919


Provided by Public Library of Science