A new varicella-zoster virus (VZV) molecular-based swab assay developed by DiaSorin Molecular LLC has been given CE marking and is now available in Europe.

The Simplexa™ VZV Swab Direct assay can detect VZV DNA from both cutaneous and mucocutaneous swab specimens and is used LIAISON MDX® instrument and complements the company’s Simplexa HSV 1 & 2 Direct kit.

Varicella-zoster virus infection causes two clinically distinct forms of disease, depending on whether an individual is experiencing a primary (chickenpox) or secondary (shingles) infection. Chickenpox is a highly contagious disease that is usually contracted in early childhood. It can cause health complications, especially in older individuals. After initial infection, VZV becomes latent in sensory nerve ganglia and can reactivate later in life to cause shingles (herpes zoster). This is a painful condition that can result in complications such as post-herpetic neuralgia and central nervous system infections.

PCR methods are the most sensitive methods available, giving 95-100% sensitivity and specificity. These methods are especially useful in distinguish VZV from herpes simplex virus (HSV) as the clinical presentation of zoster can often be confused with the dermal manifestation of HSV. 

As the VZV is a highly infectious virus with one case potentially infecting 10-12 susceptible people, any faster method employed can provide a rapid diagnosis and decision concerning proper treatment and management. 

Diagnosis in many clinical laboratories has been primarily based on a swab of vesicle fluid for culture or biopsy for electron microscopy. Serology is also a method employed and can also be used to demonstrate immunity. Recovery from primary varicella infection usually results in lifelong immunity, making recurrent disease a rare event. The disease may return in immunocompromised individuals and is of significant concern amongst pregnant women.

The vaccine for VZV has had a laboured journey into public health programmes. In the US the VZV vaccine has a universal recommendation but is not mandatory, and DiaSorin Molecular has also submitted the Simplexa VZV Swab assay to the FDA for 510(k) clearance.

In the EU, the vaccine applies mainly to high-risk groups. There are only 8 countries in the EU recommending the vaccine to children under two years of age with only a small proportion of these funded by the National Health System. Italy is the only country in the EU where vaccination is mandatory.

Although several vaccines have been available since the 1990s, it is estimated that greater than 90 percent of the population will acquire the disease by the age of 15.