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Can Antiviral Herpes Drugs Reduce the Risk of Alzheimer Disease?

Decades-old research suggests that herpes virus infections might contribute to Alzheimer's disease. Could antiviral herpes drugs help prevent dementia?
Can Antiviral Herpes Drugs Reduce the Risk of Alzheimer Dise...

There are few more devastating diagnoses than dementia. Alzheimer disease robs people of their memories, their personalities and their ability to care for themselves. It is often a tortuous decline that impacts friends and families in life-shattering ways. Despite billions of dollars spent on research and drug development, there has been little progress made against Alzheimer’s. But a review in Frontiers in Aging Neuroscience (Oct. 19, 2018) offers a glimmer of hope that antiviral herpes drugs might help attenuate the decline into dementia.

Antiviral herpes drugs like acyclovir (Zovirax), famciclovir (Famvir) or valacyclovir (Valtrex) have been available for many years. (Zovirax was first marketed by Burroughs Wellcome as an ointment in 1982 and in capsule form in 1985.) These antiviral medications are prescribed to treat herpes infections such as shingles (herpes zoster), chickenpox (varicella), genital herpes (HSV-2) and herpes labialis (cold sores caused by HSV-1).

Herpes Simplex Virus 1 and Alzheimer’s Disease:

Over 40 years ago Swedish researchers reported a connection between herpes virus infections and dementia. They noted that people with severe depression or “atherosclerotic dementia had a significantly higher incidence of herpes simplex virus” than was found in healthy controls (British Journal of Psychiatry, March, 1974).

Dr. Ball’s Radical Theory: Herpes and Dementia

Melvyn J. Ball, MD, was a pathologist at the Oregon Health and Science University. He is now retired. In 1982 he suggested that HSV1 (the herpes simplex virus that causes cold sores) might be contributing to the brain pathology of Alzheimer’s disease.

Dr. Ball knew that the herpes virus hibernates in the trigeminal ganglia in the brain. In its dormant state it doesn’t do much damage. Every once in awhile it travels down a nerve pathway to the lips or face and causes a cold sore outbreak. This can happen after exposure to bright sun at the beach or on the ski slopes. People under stress may also have an attack.

Most neuroscientists assumed that the virus only traveled downward. Dr. Ball proposed the virus could travel up and into brain tissue Canadian Journal of Neurological Sciences, Aug. 1982). A few other scientists began pursuing this radical concept.

Dr. Ruth Itzhaki Continues the Research:

Ruth Itzhaki, PhD, is a British neuroscientist. She is Professor Emeritus of Molecular Neurobiology at the University of Manchester. In 1991, her team reported that the cold sore virus (HSV-1) was prevalent in the brains of senior citizens (Journal of Medical Virology, Apr. 1991).

By 1997, Dr. Itzhaki and her colleagues had reported that the combination of HSV-1 plus the gene APOE-e4, was a strong risk factor for Alzheimer’s disease (Lancet, Jan. 25, 1997). Writing about her research in The Conversation (Oct. 19, 2018) Dr. Itzhaki states () :

“The virus can become active in the brain, perhaps repeatedly, and this probably causes cumulative damage. The likelihood of developing Alzheimer’s disease is 12 times greater for APOE4 carriers who have HSV1 in the brain than for those with neither factor.”

“We believe that HSV1 is a major contributory factor for Alzheimer’s disease and that it enters the brains of elderly people as their immune system declines with age. It then establishes a latent (dormant) infection, from which it is reactivated by events such as stress, a reduced immune system and brain inflammation induced by infection by other microbes.”

Antiviral Herpes Drugs to the Rescue?

In her recent article Dr. Itzhaki makes a crucial point:

“It’s important to note that all studies, including our own, only show an association between the herpes virus and Alzheimer’s – they don’t prove that the virus is an actual cause. Probably the only way to prove that a microbe is a cause of a disease is to show that an occurrence of the disease is greatly reduced either by targeting the microbe with a specific anti-microbial agent or by specific vaccination against the microbe.

Antiviral Herpes Drugs:

Dr. Itzhaki goes on to note:

“Excitingly, successful prevention of Alzheimer’s disease by use of specific anti-herpes agents has now been demonstrated in a large-scale population study in Taiwan. Hopefully, information in other countries, if available, will yield similar results.”

Actual Research on Antiviral Herpes Drugs Against Alzheimer’s:

In one study antiviral treatment of herpes virus infections with drugs like acyclovir, famciclovir or valacyclovir dramatically reduced the likelihood of developing dementia (Neurotherapeutics, Apr. 2018).  In that epidemiological study, roughly 28 percent of HSV patients developed dementia during the 10-year follow-up. Among similar patients treated with antiviral drugs, fewer than 6 percent progressed to dementia.

Dr. Itzhaki describes the research this way:

“Even more strikingly, a group of HSV-infected patients (N= 7, 215) who had been treated with one of various anti-herpes agents (acyclovir, famciclovir, ganciclovir, idoxuridine, penciclovir, tromantadine, valaciclovir (VCV—the biodrug of ACV, which is better absorbed) and valganciclovir), showed a dramatic reduction of almost 10 fold in the later incidence of SD [senile dementia] compared with those who received no treatment.”

From the Researchers Themselves:

The Taiwanese investigators recruited 33,448 people:

“8,362 with newly diagnosed HSV [herpes simplex virus] infections and 25,086 randomly selected sex- and age-matched controls without HSV infections…”

The study was described this way:

“This retrospective cohort study is to investigate the association between herpes simplex virus (HSV) infections and dementia, and the effects of anti-herpetic medications on the risk involved, using Taiwan’s National Health Insurance Research Database (NHIRD).

“The usage of anti-herpetic medications in the treatment of HSV infections was associated with a decreased risk of dementia. These findings could be a signal to clinicians caring for patients with HSV infections.”

Final Thoughts About Antiviral Herpes Drugs and Alzheimer Disease:

Dr. Itzhaki and her colleagues bemoan the fact that scientists have been overlooking research data linking infections and Alzheimer’s disease for three decades.

She concludes:

“Surely, now is the time to rectify the situation by determining and then using the best means of treatment at hand.”

Frontiers in Aging Neuroscience, Oct. 19, 2018

We suspect that most health professionals have never heard of the herpes virus theory of Alzheimer disease. Fewer still have read about the study from Taiwan demonstrating benefit from antiviral herpes drugs.

Not surprisingly, readers would like to know if antiviral herpes drugs might be helpful. Here is an article we wrote on this topic based on just such a question.

Other Anti-Alzheimer Disease Resources:

We have interviewed two neuroscientists who are at the cutting edge of Alzheimer disease research. You may find our one-hour interview of great interest.  These scientists discuss the role of infection in dementia and talk about the anti-viral activity of amyloid beta. Here is a link to that show.

You can listen to the streaming audio, an mp3 file, the podcast, or request a CD that you can share.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
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