Nine out of 10 Americans carry the varicella zoster virus (VZV) in a dormant state, with the potential to reactivate and cause significant brain, nerve, and organ damage, according to new research. VZV is the virus responsible for chickenpox and shingles.
While most people contract VZV in childhood, leading to chickenpox, the virus remains dormant in nerve cells and can reactivate later in life. Researchers at the University of Colorado Anschutz School of Medicine are emphasizing that this reactivation is an underrecognized cause of serious neurological and systemic diseases. Their findings suggest that at least one in three individuals will experience VZV reactivation during their lifetime.
Spectrum of Reactivation Diseases
When VZV reactivates, it can impact sensory nerves, blood vessels, and multiple organs, leading to a wide range of systemic illnesses. The most common manifestation is shingles, characterized by a painful, blistering rash typically affecting one side of the body. Shingles primarily occurs in adults over 50 and can result in debilitating nerve pain. Left untreated, the severe pain associated with shingles is a leading cause of suicide among older adults, and some patients may experience permanent facial paralysis.
Beyond the visible rash, VZV reactivation can also lead to multi-organ damage, including to the heart, eyes, lungs, and intestines, due to inflammation of nerves. The research indicates that shingles may also increase the risk of heart attacks, strokes, cognitive decline, and dementia.
The Challenge of Silent Reactivation
A significant concern raised by the study is that VZV diseases can spread internally without a rash or other discernible external signs, making them difficult to detect. Dr. Maria Nagel, the corresponding author of the study and a professor at the University of Colorado, explained that VZV is a "stealthy virus" capable of causing disease in various parts of the body without announcing its presence. This often-undiagnosed condition, known as zoster sine herpete or "internal shingles," can present as severe, one-sided burning pain with normal imaging studies, leaving the underlying cause untreated until VZV infection is identified.
Prevention and Detection
To prevent potentially irreversible complications, researchers urge prompt detection and treatment of VZV reactivation. While chickenpox cases in the U.S. have dramatically decreased by 97% since the introduction of a routine vaccine in 1995, with about 90% of children receiving the two-dose regimen, VZV remains a concern.
The chickenpox vaccine is estimated to be 90% to 98% effective. The shingles vaccine, recommended for individuals over 50 or those with weakened immune systems over 19, is given in two doses and is about 90% effective in reducing the risk of developing shingles.
However, the researchers note a critical shortage of clinicians and researchers specializing in the neurological and systemic manifestations of VZV. They emphasize the need for increased awareness among medical professionals that VZV can present in ways very different from the classic shingles presentation. When a patient exhibits a puzzling neurological or systemic condition, especially if localized to one side of the body, VZV should be considered as a potential cause, even in the absence of a visible rash.