Herpes zoster epidemiology and demographics
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; L. Katie Morrison, MD; Associate Editor(s)-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]
Overview
Before introduction of varicella vaccine in the United States in 1995, varicella was endemic, with virtually all persons being infected by adulthood. Since implementation of the varicella vaccination program, incidence has declined in all age groups, with the greatest decline among children aged 1-4 years. Data from passive and active surveillance have indicated a decline in varicella cases of 70%-84% from 1995 through 2001 (1-3). The downward trend in varicella has continued in the United States through 2005 with an approximately 90% decline in incidence from 1995 in active surveillance sites with high vaccine coverage (CDC, unpublished data).
Epidemiology and Demographics
Incidence
The incidence rate of herpes zoster ranges from 1.2 to 3.4 per 1,000 person-years among healthy individuals, increasing to 3.9–11.8 per 1,000 person‐years among those older than 65 years. [1] Similar incidence rates have been observed worldwide.[2] [3] Herpes zoster develops in an estimated 500,000 Americans each year.[4] Multiple studies and surveillance data demonstrate no consistent trends in incidence in the U.S. since the chickenpox vaccination program began in 1995.[5] It is likely that incidence rate will change in the future, due to the aging of the population, changes in therapy for malignant and autoimmune diseases, and changes in chickenpox vaccination rates; a wide adoption of zoster vaccination could dramatically reduce the incidence rate.[6] In general, herpes zoster has no seasonal incidence and does not occur in epidemics.[7]
Most studies, but not all, suggest that the overall incidence of herpes zoster is increasing in the United States and elsewhere. This increase is independent of the effect of aging of the population. However, the rate of herpes zoster in U.S. children is declining. Children vaccinated against varicella appear to have a lower risk of reactivation of vaccine-strain VZV compared with reactivation of wild-type VZV.
Several studies report that the overall incidence of herpes zoster started increasing before the varicella vaccine was introduced in the United States. The reasons for this increase are not well understood. Currently, there is no consistent evidence that increases in herpes zoster incidence in the United States have been accelerated by the varicella vaccination program.
CDC continues to study the epidemiology of herpes zoster among adults and children and to monitor the effects of the U.S. varicella and zoster vaccination programs.
Prevalence
Varicella zoster virus has a high level of infectivity and is prevalent worldwide,[8] and has a very stable prevalence from generation to generation.[9] VZV is a benign disease in a healthy child in developed countries. However, varicella can be lethal to individuals who are infected later in life or who have low immunity. The number of people in this high-risk group has increased, due to the HIV epidemic and the increase in immunosuppressive therapies. Infections of varicella in institutions such as hospitals are also a significant problem, especially in hospitals that care for these high-risk populations.[10]
In temperate zones chickenpox is a disease of children, with most cases occurring during the winter and spring, most likely due to school contact; there is no evidence for regular epidemics. In the tropics chickenpox typically occurs among older people. [11] Incidence is highest in people who are over age 55, as well as in immunocompromised patients regardless of age group, and in individuals undergoing psychological stress. Non-whites may be at lower risk; it is unclear whether the risk is increased in females. Other potential risk factors include mechanical trauma, genetic susceptibility, and exposure to immunotoxins. [12]
In one study, it was estimated that 26% of patients who contract herpes zoster eventually present with complications. Postherpetic neuralgia arises in approximately 20% of patients.[13] A study of 1994 California data found hospitalization rates of 2.1 per 100,000 person-years, rising to 9.3 per 100,000 person-years for ages 60 and up.[14] An earlier Connecticut study found a higher hospitalization rate; the difference may be due to the prevalence of HIV in the earlier study, or to the introduction of antivirals in California before 1994.[15]
References
- ↑ Dworkin RH, Johnson RW, Breuer J et al. (2007). "Recommendations for the management of herpes zoster". Clin. Infect. Dis 44 Suppl 1: S1–26. doi:10.1086/510206. PMID 17143845
- ↑ Araújo LQ, Macintyre CR, Vujacich C (2007). "Epidemiology and burden of herpes zoster and post-herpetic neuralgia in Australia, Asia and South America" (PDF). Herpes. 14 (Suppl 2): 40A–4A. PMID 17939895.
- ↑ Dworkin RH, Johnson RW, Breuer J et al. (2007). "Recommendations for the management of herpes zoster". Clin. Infect. Dis 44 Suppl 1: S1–26. doi:10.1086/510206. PMID 17143845
- ↑ Insinga RP (2005). "The incidence of herpes zoster in a United States administrative database". J Gen Intern Med. 20 (6): 748–753. doi:10.1111/j.1525-1497.2005.0150.x. PMID 16050886.
- ↑ Marin M, Güris D, Chaves SS, Schmid S, Seward JF (2007). "Prevention of varicella: recommendations of the Advisory Committee on Immunization Practices (ACIP)". MMWR Recomm Rep. 56 (RR-4): 1–40. PMID 17585291.
- ↑ Dworkin RH, Johnson RW, Breuer J et al. (2007). "Recommendations for the management of herpes zoster". Clin. Infect. Dis 44 Suppl 1: S1–26. doi:10.1086/510206. PMID 17143845
- ↑ Thomas SL, Hall AJ (2004). "What does epidemiology tell us about risk factors for herpes zoster?". Lancet Infect Dis 4 (1): 26–33. doi:10.1016/S1473-3099(03)00857-0. PMID 14720565
- ↑ Apisarnthanarak A, Kitphati R, Tawatsupha P, Thongphubeth K, Apisarnthanarak P, Mundy LM (2007). "Outbreak of varicella-zoster virus infection among Thai healthcare workers". Infect Control Hosp Epidemiol. 28 (4): 430–4. doi:10.1086/512639. PMID 17385149.
- ↑ Abendroth A, Arvin AM (2001). "Immune evasion as a pathogenic mechanism of varicella zoster virus". Semin. Immunol. 13 (1): 27–39. doi:10.1006/smim.2001.0293. PMID 11289797.
- ↑ Weller TH (1997). Varicella-herpes zoster virus. In: Viral Infections of Humans: Epidemiology and Control. Evans AS, Kaslow RA, eds. Plenum Press. pp. 865–892. ISBN 978-0306448553.
- ↑ Wharton M (1996). "The epidemiology of varicella-zoster virus infections". Infect Dis Clin North Am 10 (3): 571–81. PMID 8856352
- ↑ Thomas SL, Hall AJ (2004). "What does epidemiology tell us about risk factors for herpes zoster?". Lancet Infect Dis 4 (1): 26–33. doi:10.1016/S1473-3099(03)00857-0. PMID 14720565
- ↑ Volpi A (2007). "Severe complications of herpes zoster" (PDF). Herpes. 14 (Suppl 2): 35A–9A. PMID 17939894.
- ↑ Coplan P, Black S, Rojas C (2001). "Incidence and hospitalization rates of varicella and herpes zoster before varicella vaccine introduction: a baseline assessment of the shifting epidemiology of varicella disease". Pediatr Infect Dis J. 20 (7): 641–5. PMID 11465834.
- ↑ Weaver BA (2007). "The burden of herpes zoster and postherpetic neuralgia in the United States". J Am Osteopath Assoc. 107 (3 Suppl): S2–7. PMID 17488884.