August 2, 2022

expert reaction to a cell study looking at potential involvement of two viruses (VSV and HSV) in Alzheimer’s Disease

A cell study published in Journal of Alzheimer’s Disease looks at the potential involvement of varicella zoster virus (VSV) in Alzheimer’s disease via reactivation of quiescent herpes simplex virus (HSV) type 1.

Prof Rob Howard, Professor of Old Age Psychiatry, UCL, said:

“Some researchers have suggested for many years that Alzheimer’s disease may be caused by herpes viruses and it is fair to say that most workers in the field have remained sceptical about these claims. There is nothing in these new data that will dispel this scepticism, despite the ambitious claims made by the authors.”

Dr Paresh Malhotra, Reader in Cognitive & Behavioural Neurology, at Imperial College London, said:

“Following on from other research suggesting that viral infection may slightly increase the risk of Alzheimer’s Disease and other causes of Dementia, these researchers have examined the effects of two common herpes viruses – VZV (responsible for chickenpox and shingles) and HSV (the herpes virus which causes cold sores) – on cells grown under lab conditions.

“They found that, on its own, VZV did not lead to Alzheimer’s like changes in cells and tissue grown in the laboratory. But when cells previously infected with HSV were then infected by VZV as well, this reactivated the latent HSV and caused microscopic changes similar to those seen in the brains of people with Alzheimer’s.

“These are laboratory findings and do not directly implicate these viruses as the main cause of Alzheimer’s Disease, but the results are important and should continue to stimulate research to understand how much infection, with these viruses and other micro-organisms, contributes to greater risk and worsening of Alzheimer’s and other causes of Dementia.”

‘Potential Involvement of Varicella Zoster Virus in Alzheimer’s Disease via Reactivation of Quiescent Herpes Simplex Virus Type 1’ by Dana Cairns et al. was published in Journal of Alzheimer’s Disease at 00:01 UK time on Tuesday 4^th August.

Declared interests

Prof Rob Howard: “No conflicts.”

Dr Paresh Malhotra: “I receive research funding from NIHR, MRC, Dementia Platforms UK, British Heart Foundation and Alzheimer’s Society. I am a member of the Alzheimer’s Research UK Grant Review Board and Vice Chair of the Alzheimer’s Society Research Strategy Council. I co-lead two studies in the DPUK Neuroimmunology Theme.”