Study highlights increase in VZV-induced CNS infections and dementia risk

Researchers from Fujita Health University, Japan, saw an increase in adult central nervous system infections (CNS), mainly aseptic meningitis caused by the Varicella Zoster -Virus (VZV), after 2019. The researchers emphasized the potential of Zoster -vaccination. In the meantime, CNS infection through herpes viruses, including VZV, can contribute to the progression of dementia. Moreover, the potential effect of zoster -vaccines in preventing dementia progression by reducing VZV reactivation is also emphasized.

The Varicella Zoster -Virus (VZV), a contagious virus of the herpes virus family, is primarily known to cause it in children and shingles in adults. But lately it has been reported that this virus also activates serious complications such as infections of the central nervous system (CNS). Researchers from Fujita Health University, Japan, conducted an extensive study with 10 years (2013-2022), to identify the VZV-related infections that influence the central nervous system. Their studies reveal a clear increase in adult VZV-related CNS infections, in particular since 2019. The findings were published in part 30, number 12 from the Emerging infectious diseases Journal on December 30, 2024.

The study was led by Professor Tetsushi Yoshikawa, together with Hiroki Miura and Ayami Yoshikane from the Pediatrics department, Fujita Health University School of Medicine. The researchers analyzed cerebrospinal liquid samples of 615 adult patients with suspected CNS infections. VZV -DNA was most detected in these patients, with his presence in 10.2% of cases, and aseptic meningitis is the most common infection.

The data from 2019 to 2022 showed that there was a noticeable increase in VZV-DNA-positive cases, so that a clearly temporary cluster was formed during this period. Professor Yoshikawa emphasized the results of the patient’s demographic analysis and reported that “the share of aseptic meningitis increased from 50% to 86.8% between 2013 and 2019 and 2022.” He adds: “Similar to the rise in Herpes Zoster -cases due to VZV reactivation in the elderly, we believe that this increase is also linked to VZV reactivation.”

The universal Varicella vaccination, introduced in Japan in 2014, has reduced the natural booster effects from re-bleeding on the virus. This may accelerate the decrease in immunity, leading to VZV reactivation, especially in cases such as shingles. The researchers emphasize the relationship between vaccination and the current scenario and say: “The increase in CNS infections induced by VZV coincides with changes in Varicella vaccination programs and emphasizes the need for better preventive strategies.”

In addition, the researchers investigated trends in CNS infection induced by VZV during the observation period using the circular spatial scan statistics from Kulldorff. As a result, it was confirmed that from 2019 to 2022 there was an accumulation of VZV-related CNS infections. Although no direct cause had been established, six patients developed CNS infections after receiving COVID-19 vaccines.

“Further studies are needed to understand these interactions,” Yoshikawa notes. None of the eligible patients in this study had received the zoster vaccine, which was introduced in Japan in 2016. The number of VZV-related CZS infections underlines the importance of zoster vaccination in adults.

The research team emphasizes the broader implications of their findings, which states that the reactivation of VZV in the central nervous system is linked to an increased risk of dementia, including Alzheimer’s disease. They assume: “If the prevention of VZV-related aseptic meningitis by Herpes Zoster vaccination is possible, these vaccinations can play a crucial role in reducing these risks of dementia.”

In order to tackle growing concern, the research team argued for expanding public health initiatives to promote zoster vaccination between risk populations.

Our research underlines the need for proactive measures to prevent shingles not only, but also serious neurological complications associated with VZV. “

Professor Tetsushi Yoshikawa, Department Pediatrics, Fujita Health University School of Medicine

With the rise of the aging population and the central nervous system, infections, the study requests urgent action to evaluate and implement extensive vaccination strategies to prevent infections from CZS in the future.