The root causes of dementia remain unclear. Consequently, highly effective preventive or therapeutic strategies to combat this disorder don’t exist. Although viruses have never been shown to be a clear cause of dementia, herpesviruses have drawn attention because of their capacity to remain latently in the central nervous system and reactivate.
To examine the possibility the varicella zoster virus plays a role in dementia, researchers at Stanford University and Heidelberg University took advantage of an unusual decision in Wales regarding the use of Zostavax, a shingles vaccine composed of live, weakened varicella virus (Oka strain) (Eyting M, Xie M, Heß S, Geldsetzer S. “Causal Evidence that Herpes Zoster Vaccination Prevents a Proportion of Dementia Cases.” medRxiv [Preprint]. 2023 May 25:2023.05.23.23290253)). People in Wales born after Sept. 2, 1933, were eligible to receive Zostavax, whereas those born before that date were not. There was no plausible reason for why those born one week prior to Sept. 2, 1933, should differ from those born one week later. Therefore, these two groups were studied to determine differences in the development of dementia.
The authors found a 19.9% relative reduction in the occurrence of dementia in the vaccinated group. Apart from preventing shingles and dementia, the herpes zoster vaccine had no other effects on common causes of morbidity or mortality. The authors concluded, “Our findings strongly suggest an important role of the varicella zoster virus in the etiology of dementia.” It will be interesting to see the results of prospective studies using the currently licensed Shingrix vaccine to determine whether this finding holds up.
Contributed by: Paul A. Offit, MD
The root causes of dementia remain unclear. Consequently, highly effective preventive or therapeutic strategies to combat this disorder don’t exist. Although viruses have never been shown to be a clear cause of dementia, herpesviruses have drawn attention because of their capacity to remain latently in the central nervous system and reactivate.
To examine the possibility the varicella zoster virus plays a role in dementia, researchers at Stanford University and Heidelberg University took advantage of an unusual decision in Wales regarding the use of Zostavax, a shingles vaccine composed of live, weakened varicella virus (Oka strain) (Eyting M, Xie M, Heß S, Geldsetzer S. “Causal Evidence that Herpes Zoster Vaccination Prevents a Proportion of Dementia Cases.” medRxiv [Preprint]. 2023 May 25:2023.05.23.23290253)). People in Wales born after Sept. 2, 1933, were eligible to receive Zostavax, whereas those born before that date were not. There was no plausible reason for why those born one week prior to Sept. 2, 1933, should differ from those born one week later. Therefore, these two groups were studied to determine differences in the development of dementia.
The authors found a 19.9% relative reduction in the occurrence of dementia in the vaccinated group. Apart from preventing shingles and dementia, the herpes zoster vaccine had no other effects on common causes of morbidity or mortality. The authors concluded, “Our findings strongly suggest an important role of the varicella zoster virus in the etiology of dementia.” It will be interesting to see the results of prospective studies using the currently licensed Shingrix vaccine to determine whether this finding holds up.
Contributed by: Paul A. Offit, MD