The fact that there may be a correlation between some viral infections and the onset of diseases affecting the cognitive system has long been a topic of debate among experts in these research areas. First of all, let’s think of the cases of long covid and the so-called “cognitive fog”, a sort of umbrella term used to describe a variety of cognitive disorders that persist even for months following the infection with SARS-CoV-2. But the question does not only concern Covid, and, remaining on this theme, a group of scientists has analyzed the possible correlation between vaccination againstherpes zoster (i.e. shingles) and the onset of dementia.
Beyond infections: the hidden damage caused by viruses
by Roberta Villa
The study, which involved nearly 300,000 people, is currently available on medRxiv, a server that collects scientific articles that have not yet been reviewed by other experts and are therefore waiting to be corrected and eventually accepted by scientific journals for their official publication. The results – which must therefore be taken with due caution – seem to have revealed a fair reduction in the risk – about 20% – of developing dementia in subjects who received the Zostavax vaccine.
I have suffered from recurring herpes zoster for decades, can getting the vaccine eradicate it?
In Wales, the vaccination campaign against herpes zoster with the Zostavax vaccine was launched on 1 September 2013, aimed at people under 80 (this because, as reported by a news of Naturesome data suggest that this type of vaccination is more effective in the population under the age of 80). The group of researchers, led by Pascal Geldsetzer of Stanford University in California (United States), examined the registered health data relating to almost 300,000 people who were vaccinated or not, all born between September 1, 1925 and September 1, 1942 (excluding those who had received a diagnosis of dementia on a date prior to the start of the vaccination campaign). According to the results, in the “group” of those who had received the vaccine there seems to be a relative reduction in the risk of developing dementia equal to 19.9%.
I had the chickenpox vaccine as a child, am I protected from shingles?
However, the same authors underline some limitations of this study, such as for example the fact that the follow-up lasted only eight years: this implies that there is currently no information relating to the effect of the vaccine on the onset of dementia in the longer term. Furthermore, the authors write in the conclusions, the study concerns only the Zostavax vaccine: a second vaccine against shingles (called Shingrix) was made available in the United Kingdom in September 2021, when however the follow-up period was it was already finished. The study also leaves some questions open: first of all, it is not clear why the effect is much more evident in the female population than in the male one. What is certain is that further research will be needed to confirm (or not) these observations, which certainly arouse great interest.