Incidence, risk factors and prevention of herpes zoster: review article

Herpes zoster (Shingles; Zona) is an acute infectious skin disease that is caused by the reactivation of varicella zoster virus (VZV). After the initial infection (chickenpox) or vaccination, the virus remains inactive or latent in the dorsal root ganglia (DRG); when decreasing cell mediated immunity (CMI) occurs, the virus is reactivated from a latent phase to a lytic phase and frequently replicated in the dorsal ganglion cells then move to the sensory nerves into the skin and causes herpes zoster, which is typically characterized by painful neuralgia and unilateral dermatomal vesicular rash that normally lasts 3 to 5 weeks. The most common complication of herpes zoster is chronic pain owing to postherpetic neuralgia (PHN), which is estimated to occur in approximately 20% of the people aged 50 and over. Although herpes zoster is rarely fatal, the pain related to the acute phase of herpes zoster and subsequent PHN can cause psychological distress, physical disability, impaired sleep and consequently negatively affect the quality of life that can be significantly reduced by all of these occurrences. Due to increasing trend in the incidence of herpes zoster and increasing older people population, it will be expected that herpes zoster and subsequent PHN cause a significant economic burden to the healthcare system, the government, and families along with reducing the quality of life. The average lifetime risk of herpes zoster is estimated to be approximately 30% in developing countries. Although the risk of herpes zoster significantly increases with increasing age and diminished immune system function, any factor impacting on VZV-specific humoral and cellular immune responses may affect the risk of herpes zoster. This paper is provided an overview of the incidence and potential risk factors of herpes zoster with emphasis on the role of micronutrients and their deficiencies in the impaired immune system function. Also, the common method for prevention by zoster vaccine and the role of micronutrients in the efficacy of vaccination are shown.