From the Guidelines
Varicella-Zoster Virus (VZV) is a highly contagious pathogen that causes both chickenpox (varicella) and shingles (herpes zoster), with the potential for severe complications, particularly in immunocompromised individuals. VZV initially causes chickenpox, typically in childhood, characterized by an itchy, blister-like rash [ 1 ]. After recovery, VZV remains dormant in nerve tissues for years or decades. Later in life, the virus can reactivate as shingles, producing a painful, localized rash along nerve pathways.
Key Characteristics of VZV
- VZV spreads through direct contact with fluid from blisters or through respiratory droplets [ 1 ]
- The virus belongs to the herpesvirus family and, like other herpesviruses, establishes lifelong latency in the host
- Treatment for active infections may include antiviral medications such as acyclovir, valacyclovir, or famciclovir, particularly for shingles or severe chickenpox cases [ 1 ]
- Prevention includes the varicella vaccine for chickenpox and the zoster vaccine for shingles in older adults
Clinical Considerations
- High-dose IV acyclovir remains the treatment of choice for VZV infections in compromised hosts [ 1 ]
- Oral acyclovir, famciclovir, and valacyclovir are beneficial for VZV infections in otherwise healthy hosts
- Recipients of allogeneic blood and bone marrow transplants routinely take acyclovir or valacyclovir during the first year following transplant for the prevention of VZV and HSV reactivation [ 1 ]
From the Research
Definition and Characteristics of Varicella-Zoster Virus (VZV)
- Varicella-Zoster Virus (VZV) is a ubiquitous human alphaherpesvirus that causes varicella (chickenpox) and herpes zoster (shingles) 2.
- VZV establishes latency in cells of the dorsal root ganglia, and its reactivation causes herpes zoster, a localized, painful, vesicular rash involving one or adjacent dermatomes 2.
- The VZV virion consists of a nucleocapsid surrounding a core that contains the linear, double-stranded DNA genome; a protein tegument separates the capsid from the lipid envelope, which incorporates the major viral glycoproteins 2.
Clinical Manifestations and Epidemiology
- Varicella is a common childhood illness, characterized by fever, viremia, and scattered vesicular lesions of the skin 2.
- The incidence of herpes zoster increases with age or immunosuppression 2.
- VZV is found in a worldwide geographic distribution but is more prevalent in temperate climates 2.
- Severe pain is the major cause of acute and chronic morbidity in patients with herpes zoster, and postherpetic neuralgia (PHN) is the most common complication of herpes zoster 3.
Treatment and Prevention
- Acyclovir is licensed for treatment of varicella and herpes zoster, and acyclovir, valacyclovir, and famciclovir are approved for herpes zoster 2.
- Passive antibody prophylaxis with varicella-zoster immune globulin is indicated for susceptible high-risk patients exposed to varicella 2.
- A live attenuated varicella vaccine (Oka/Merck strain) is now recommended for routine childhood immunization 2.
- Newer anti-VZV drugs, such as valaciclovir and famciclovir, have been developed and have enlarged the therapeutic options to treat VZV infections 4, 5.
- Foscarnet, a direct inhibitor of the viral DNA polymerase, is the drug of choice for the treatment of TK-deficient VZV mutants emerging under acyclovir therapy 4, 5.