While Itzhaki’s work has been widely recognized, it has met considerable resistance in the United States. A statement at the top of his piece may explain why. “Infected” is not the same as “affected.” Yes, not all of those who have HSV1 will develop AD. Other factors influence the risk. Similarly, another virus in the herpes family, varicella, infects most people and causes chicken pox; yet, only a small portion experience a viral reactivation and develop shingles decades later.

Itzhaki’s group has tested the viability of a vaccine against HSV1. Mice treated with an experimental vaccine can be exposed to HSV1 without the virus establishing persistent latent infections, unlike unvaccinated mice.16 Until a human vaccine can be developed, there are interventions currently available. Antiviral medications, such as acyclovir and valacyclovir, are highly effective against HSV1. As mentioned above, acyclovir prevented the accumulation of amyloid in virally infected neurons in culture. However, acyclovir has poor oral bioavailability and is rapidly eliminated (half-life of 3 hours).

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The pro-drug, valacyclovir has 3-5 times greater bioavailability.17,18 Moreover, valacyclovir is safe and well-tolerated unless there is renal impairment. In my experience, valacyclovir can be administered for years to treat virally-mediated illnesses without any detectable adverse events.19 Similarly, a group of patients with multiple sclerosis were treated for two years with valacyclovir with no adverse consequences.20

In summary, if findings by the Swedish group4 and Itzhaki are correct, and a shift in intrinsic assumptions about Alzheimer’s can occur, then antiviral treatments currently available could potentially eliminate a significant proportion of Alzheimer’s cases.21 The low cost and risk of obtaining blood work on Alzheimer’s patients and administering valacyclovir comes with a potentially huge upside. The alternative is to wait for the autopsy.

Theodore Henderson, MD, PhD, is a psychiatrist in Denver who specializes in the diagnosis of complex adult, child, and adolescent psychiatric cases. His website is www.childpsychiatristdenver.com.


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