A new study from Japan reveals a troubling surge in adult central nervous system (CNS) infections linked to varicella zoster virus (VZV), with cases rising sharply since 2019. CNS infection by herpes viruses, including VZV, may contribute to the progression of dementia. The study makes the case for the zoster vaccine.
Published in Emerging Infectious Diseases, the research (“Increase in Adult Patients with Varicella Zoster Virus-Related Central Nervous System Infections, Japan”) highlights that VZV reactivation is now a leading cause of aseptic meningitis in adults, raising concerns about long-term neurological effects—including dementia risks.
The varicella zoster virus (VZV), an infectious virus from the herpes virus family, is primarily known to cause varicella in children and shingles in adults. But lately, this virus has also been reported to trigger severe complications like central nervous system (CNS) infections.
These findings are the result of a ten-year study analyzing 615 adult CNS infection cases (using cerebrospinal fluid samples), undertaken at Fujita Health University, Japan. The data from 2019 to 2022 revealed that there was a noticeable rise in VZV DNA-positive cases, forming a distinct temporal cluster during this period.
VZV DNA was detected in 10.2 percent of patients, with cases spiking post-2019. Furthermore, the study identified that aseptic meningitis cases jumped from 50 percent (2013-2018) to 86.8 percent (2019-2022).
Perhaps the main concern is that no studied patients had received the zoster vaccine, despite its availability since 2016. Consequently, the researchers are urging health authorities to take increased public health measures, including zoster vaccination. This is a necessary step to curb infections and potential dementia links.
The universal varicella vaccination, introduced in Japan in 2014 and in many countries worldwide, has reduced the natural booster effects from re-exposure to the virus. This potentially accelerates the immunity decline, leading to VZV reactivation, especially in cases like shingles. The researchers emphasize the connection between the vaccination and the current scenario, saying, “The increase in VZV-induced CNS infections coincides with changes in varicella vaccination programs and emphasizes the need for better preventive strategies.”
Varicella is vaccine used to prevent chickenpox; zoster is a vaccine used to prevent herpes zoster, commonly known as shingles.
By using a technique called Kulldorff’s circular spatial scan statistics, this confirmed the accumulation of VZV-related CNS infections.
The scientists conclude that the prevention of VZV-related aseptic meningitis through herpes zoster vaccination is possible, these vaccinations could play a pivotal role in mitigating these risks of dementia.”
Also available are VZ immunoglobulins. These are concentrated antibody preparations that provide immediate short-term protection against disease for individuals at high risk of severe disease or serious complications from the disease.
The study was led by Professor Tetsushi Yoshikawa, along with Hiroki Miura and Ayami Yoshikane from the Department of Pediatrics, Fujita Health University School of Medicine.
