The link between shingles and an increased risk of developing dementia has now been established by several studies. And the good news is that a British study has just confirmed the role of vaccination against this disease – caused by the reactivation of the varicella-zoster virus in elderly or immunocompromised people – in reducing the risk of developing Alzheimer’s-type diseases.
This positive correlation was already known. But the existing data was limited until now to the analysis of people who had received the live attenuated vaccine, now abandoned in most countries, in favor of a recombinant vaccine. Administered in France under the brand name Shingrix, it is more effective in the fight against shingles. However, according to the work of British researchers from the University of Oxford, published a few days ago in “Nature Medicine”, this new vaccine is “associated with a significantly lower risk of dementia in the six years following vaccination”.
A natural experiment
In detail, the study concludes that there was “a 17% increase in time without a diagnosis” of dementia following administration of the recombinant vaccine, or “an additional 164 days lived without a diagnosis of dementia in those subsequently affected.” The authors now call for the design of a large-scale controlled trial to confirm these results.
Indeed, this study is currently based on the analysis of data from the American population – where the transition between the live vaccine and the recombinant vaccine was rapid and massive, and therefore could serve as a natural experiment for researchers – as well as the comparison between the effects of the shingles vaccine and those of two other vaccines widely used among seniors: the one against influenza and the one against tetanus-diphtheria-pertussis.
A very common disease
Shingles is a very common disease. As the Health Insurance reminds us, a cure for chickenpox does not result in the virus disappearing from the patient’s body. In fact, the microbe “remains ‘dormant’ at the root of the nerves in the nerve ganglia”, and can reactivate at any time, including years later. Shingles then mainly results in a painful skin rash, which can be accompanied by persistent symptoms.
It mainly occurs in people with weakened immune systems and in the elderly. According to the High Authority for Health (HAS), 1% of people over 80 were affected between 2008 and 2021, and 2,600 people were hospitalized each year during this period because of this disease, 72% of whom were over 65 years old.
In France, since March 2024, the HAS has recommended the vaccination of immunocompromised people aged 18 and over and all adults aged 65 and over with the recombinant vaccine Shingrix. The latter has an efficacy of more than 79% in the onset of shingles, and also very significantly reduces the risk of developing lasting symptoms.
