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Background
Varicella vaccine (Varivax, Merck & Co., Whitehouse Station, NJ) immunization is recommended for children over 12 months of age who do not have a history of having had varicella (chicken pox). The Advisory Committee on Immunization Practices (ACIP) recommends that children be immunized with two doses of varicella vaccine, with the first dose administered between 12 and 15 months of age, and a second dose administered between 4 and 6 years of age. In addition, the ACIP recommends that other persons who have not been immunized and have no history of varicella receive two doses of vaccine. Children, adolescents and adults who previously received one dose of varicella vaccine should receive a second one.
Healthy adolescents past their 13th birthday and adults who have not been immunized and have no history of varicella may also be immunized and require two doses of vaccine. The CDC recommends vaccination of adolescents greater than or equal to 13 years of age and adults at high risk for exposure or transmission. Groups at high risk include:
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Adolescents and adults living in households with children; and
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Persons who live or work* in environments where transmission of chicken pox is likely (e.g., teachers of young children, day care employees, and residents and staff members in institutional settings); and
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Persons who live or work* in environments where transmission of chicken pox can occur (e.g., college students, inmates and staff members of correctional institutions, and military personnel); and
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Non-pregnant women of childbearing age; and
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International travelers*.
*Note: Some Aetna plans exclude coverage of vaccinations for work or for travel. Please check benefit plan descriptions for details.
Very few people escape childhood without contracting chicken pox. The recommendation is that all individuals under 21 years of age who do not have a clear history of chicken pox should be assumed to be susceptible and can be immunized. Adults over 21 who have no history of chicken pox should be tested for immunity and, if they are susceptible, should be immunized. Five to ten percent of the adult population is probably susceptible. Seventy percent of 18 year olds have been found to be immune, even if they have no clear history of having had chicken pox.
Children 12 months to 12 years of age should receive a 0.5 mL dose of varicella vaccine administered subcutaneously. A second dose of varicella vaccine should be given a minimum of 3 months later. Adolescents and adults 13 years of age and older should receive a 0.5 mL dose administered subcutaneously at an elected date and a second 0.5 mL dose 4 to 8 weeks later.
Varicella vaccine is contraindicated in certain individuals, including persons with an immunodeficient condition or receiving immunosuppressive therapy, persons with active untreated tuberculosis, and women who are pregnant.
The FDA has approved a combined attenuated live virus vaccine containing measles, mumps, rubella, and varicella viruses (MMRV) (ProQuad injection, Merck & Co., Whitehouse Station, NJ) for use in children aged 12 months to 12 years. It is also approved for use in this population if a second dose of measles, mumps, and rubella vaccine is to be administered.
The approval was based on study data showing the immunogenicity, antibody persistence, and safety of the combination vaccine to be similar with that of its previously approved components (measles, mumps, and rubella (MMR) and varicella). The incidence of adverse events including those most commonly reported (injection site reactions, nasopharyngitis, cough) was similar between the treatment groups.
Herpes zoster (HZ) is the consequence of re-activation of the varicella zoster virus (VZV) that remains latent since primary infection (varicella). The overall incidence of HZ is about 3 per 1000 of the population per year increasing to 10 per 1000 per year by age 80. Approximately half of persons reaching age 90 years will have had HZ. In approximately 6 %, a second episode of HZ may occur; usually several decades after the first attack. The most common complication of HZ is post-herpetic neuralgia (PHN), defined as significant pain or dysaesthesia present 3 months or more following HZ. More than 5 % of the elderly have PHN at 1 year after acute HZ. Reduced cell-mediated immunity to HZ occurs with aging, which may be responsible for the increased incidence in the elderly and from other causes such as tumors, human immunodeficiency virus infection as well as immunosuppressant drugs. Diagnosis of PHN is usually clinical from typical unilateral dermatomal pain and rash. Prodromal symptoms, pain, itching and malaise, are common (Johnson and Whitton, 2004).
In a randomized, controlled, multi-center study, Oxman and colleagues (2005) examined if vaccination against VZV would decrease the incidence, severity, or both of HZ and PHN among older adults. A total of 38,546 adults aged 60 years or older were enrolled in this study. The vaccine used was a live attenuated Oka/Merck VZV vaccine. Herpes zoster (shingles) was diagnosed according to clinical and laboratory criteria. The pain and discomfort associated with HZ were measured repeatedly for 6 months. The primary end point was the burden of illness due to HZ, a measure affected by the incidence, severity, and duration of the associated pain and discomfort. The secondary end point was the incidence of PHN. More than 95 % of the subjects continued in the study to its completion, with a median of 3.12 years of surveillance for HZ. A total of 957 confirmed cases of HZ (315 among vaccine recipients and 642 among placebo recipients) and 107 cases of PHN (27 among vaccine recipients and 80 among placebo recipients) were included in the efficacy analysis. The use of the zoster vaccine reduced the burden of illness due to HZ by 61.1 % (p < 0.001), reduced the incidence of PHN by 66.5 % (p < 0.001), and reduced the incidence of HZ by 51.3 % (p < 0.001). Reactions at the injection site were more frequent among vaccine recipients but were generally mild. These researchers concluded that the zoster vaccine significantly reduced morbidity from HZ and PHN among older adults.
In May 2006, the FDA approved Zostavax (Merck & Co., Inc., Whitehouse Station, NJ), a vaccine for use to reduce the risk of HZ in people aged 60 years and older. Zostavax is administered subcutaneously in one single injection, preferably in the upper arm. The most common adverse effects in individuals who received Zostavax were redness, pain and tenderness, swelling at the site of injection, itching, as well as headache.
The FDA approved prescribing information indicates that zoster vaccine is not indicated for the treatment of herpes zoster or post-herpetic neuralgia. Zoster vaccine is a live attenuated virus vaccine, and the labeling states that zoster vaccine is contraindicated in the following persons:
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Those with a history of anaphylactic/anaphylactoid reaction to gelatin, neomycin, or any other component of the vaccine;
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Those with a history of primary or acquired immunodeficiency states including leukemia; lymphomas of any type, or other malignant neoplasms affecting the bone marrow or lymphatic system; or AIDS or other clinical manifestations of infection with human immunodeficiency viruses;
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Persons on immunosuppressive therapy, including high-dose corticosteroids;
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Persons with active untreated tuberculosis;
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Women who are or may be pregnant.
Zostavax is a live attenuated virus vaccine and is contraindicated in immunosuppressed persons, including persons with a history of primary or acquired immunodeficiency states including leukemia, lymphomas of any type, or other malignant neoplasms affecting the bone marrow or lymphatic system; with AIDS or other clinical manifestations of infection with human immunodeficiency viruses; and with active untreated tuberculosis. Zostavax is also contraindicated in persons on immunosuppressive therapy, including high-dose corticosteroids, and in women who are or may be pregnant.
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