Vaccine Preventable Diseases

Varicella

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Advisory Committee on Immunization Practices (ACIP) Recommendations

Infants and Children
- All children without contraindications should receive two doses of varicella vaccine (trade name: Varivax®) after 1 year of age and at least 3 months apart. The first dose should be administered between 12 and 15 months of age and the second between 4 and 6 years of age, generally at the same time as measles-mumps-rubella combination vaccine (abbreviation: MMR; trade name: M-M-R II®).
- The CDC recommends that MMR and varicella vaccine be administered separately albeit simultaneously for the first dose in order to reduce the risk of infant fever and febrile seizures, but the measles-mumps-rubella-varicella combination vaccine (abbreviation: MMRV; trade name: ProQuad®) vaccine can be administered for the second dose.

Adults
- The ACIP recommends all persons over 13 years of age without evidence of varicella immunity receive 2 doses of varicella vaccine separated by a minimum of 4 weeks. Immunity to varicella is especially important for health care personnel [3, 9].

For More Information
ACIP recommendations: http://www.cdc.gov/vaccines/hcp/acip-recs/
Immunization schedules: http://www.cdc.gov/vaccines/schedules/index.html
 

Disease 

Varicella is an acute disease caused by the DNA herpesvirus varicella zoster virus (VZV). VZV is transmitted via the respiratory route. The incubation period generally lasts about 15 days. Symptoms of primary infection with VZV, also known as chickenpox, include mild fever, malaise and a generalized vesicular rash.

Although varicella disease is usually mild, there are potentially serious complications including bacterial infection of skin lesions, pneumonia, Reye syndrome, cerebellar ataxia, aseptic meningitis or encephalitis. Infants under 1 year of age have an increased risk of complications.

Congenital varicella syndrome, resulting from maternal primary infection with varicella during the first 20 weeks of gestation, is associated with low birth weight, localized muscular atrophy, skin scarring and eye and neurologic abnormalities.

Herpes zoster, also known as shingles, occurs after reactivation of latent VZV and is associated with aging, immunosuppression, and other factors. Between 0.5 and 1 million episodes of herpes zoster occur in the United States every year, and half of all persons living until age 85 will develop zoster [3].

Vaccine

Varicella vaccine is a live attenuated viral vaccine. MMRV is a combination vaccine that includes measles, mumps, rubella and varicella vaccines [3].

Vaccine Effectiveness: Detectable antibody appears in approximately 97% of children after one dose of varicella vaccine. Vaccine efficacy is estimated to be 70-90% against varicella infection and 90-100% against moderate to severe varicella disease after a single dose and approximately 95% after two doses [3].

Vaccine Safety: Similar adverse reaction profiles exist for MMRV and varicella vaccination. Mild local reactions such as pain and erythema are the most common adverse reactions following varicella vaccination, reported in roughly 19% of children. Generalized rash is reported in 3% of children after receiving the second dose. Systemic reactions are uncommon. Mild zoster illness resulting from a latent infection with varicella vaccine virus has been reported. This has been very rarely associated with viral meningitis, although affected patients without immune deficiencies recover fully without any lasting effects. The vaccine can also cause hepatitis if mistakenly administered to severely immune deficient individuals [3]. See the Do Vaccines Cause Hepatitis, the Do Vaccines Cause Meningitis or Encephalitis, the Do Vaccines Cause Disseminated Varicella Infection, and the Do Vaccines Cause Vaccine-Strain Viral Reactivation summaries for more details.

Vaccines which may induce fever may also rarely induce febrile seizures. Febrile seizures are a common and typically benign childhood condition, occurring in 2-5% of children at some point during their first five years of life. Febrile seizures have an estimated background incidence of 240–480 per 100,000 person-years in children under five years, although this varies considerably by age, genetics, co-morbidities and environmental risk factors. There are no long-term effects of simple febrile seizures, with the possible exception of an increased risk of recurrence [52-55]. Febrile seizures occur at a rate of about 1 per 2,500 doses of MMR and 1 per 1,250 doses of MMRV. However, there is no increased risk of fever or febrile seizures in children receiving their second dose of measles-containing vaccine at 4 to 6 years of age, whether given MMR or MMRV [56]. See the Do Vaccines Cause Seizures summary for more details.

Although transmission of varicella vaccine virus is rare, it may very occasionally occur if a recently vaccinated person develops a rash. To be safe, close contact with persons without varicella immunity at high risk of complications, especially those who are immunocompromised, should be avoided until such a rash has disappeared [3].

Contraindications and Precautions: Severe allergic reaction (e.g. anaphylaxis) to a previous dose or vaccine component is a contraindication to further vaccination with any varicella-containing product. Other contraindications include pregnancy and altered immunity. The following is a direct excerpt from the 2007 ACIP recommendations regarding the contraindication of varicella vaccine in persons with altered immunity:

“Single-antigen varicella and combination MMRV vaccines are not licensed for use in persons who have any malignant condition, including blood dyscrasias, leukemia, lymphomas of any type, or other malignant neoplasms affecting the bone marrow or lymphatic systems. Combination MMRV vaccine should not be administered to persons with primary or acquired immunodeficiency, including immunosuppression associated with AIDS or other clinical manifestations of HIV infections, cellular immunodeficiencies, hypogammaglobulinemia, and dysgammaglobulinemia. Combination MMRV vaccine should not be administered as a substitute for the component vaccines when vaccinating HIV-infected children.

Varicella vaccines should not be administered to persons who have a family history of congenital or hereditary immunodeficiency in first-degree relatives (e.g., parents and siblings) unless the immune competence of the potential vaccine recipient has been clinically substantiated or verified by a laboratory.

Varicella vaccines should not be administered to persons receiving high-dose systemic immunosuppressive therapy, including persons on oral steroids >2 mg/kg of body weight or a total of >20 mg/day of prednisone or equivalent for persons who weigh >10 kg, when administered for >2 weeks. Such persons are more susceptible to infections than healthy persons. Administration of varicella vaccines can result in a more extensive vaccine-associated rash or disseminated disease in persons receiving immunosuppressive doses of corticosteroids. This contraindication does not apply to persons who are receiving inhaled, nasal, or topical corticosteroids or low-dose corticosteroids as are used commonly for asthma prophylaxis or for corticosteroid-replacement therapy.” [9]

Current moderate to severe acute illness is a precaution to any vaccination. Recent receipt of antibody-containing blood products is a precaution to both varicella and MMRV vaccination and may require waiting until the antibodies wane before administering the vaccine. Personal or family history of seizures is a precaution to MMRV vaccination [3, 9].

For more details, please see the most recent ACIP recommendations (http://www.cdc.gov/vaccines/hcp/acip-recs/).

Considerations in Pregnancy: Varicella vaccine is a live attenuated vaccine and is thus contraindicated during pregnancy. Having a pregnant household member is not a contraindication to varicella vaccination.

Women who are vaccinated for varicella should avoid becoming pregnant for a month after each injection. If a pregnant woman is inadvertently vaccinated or becomes pregnant within 4 weeks after varicella vaccination, she should be counseled as to the potential effects on the fetus, but this should not be considered an indication for termination of the pregnancy.

The theoretical concerns stem from the fact that wild-type varicella poses a low risk of development of congenital varicella syndrome and its associated birth defects; however, since the virulence of the attenuated vaccine virus is substantially less than the wild-type virus, the risk to the fetus from the vaccine, if any, should be even lower. The VARIVAX Pregnancy Registry has monitored the maternal and fetal outcomes of pregnant women who were inadvertently administered varicella vaccine up to 3 months before or at any time during pregnancy since 1995 and no birth defects consistent with congenital varicella syndrome have been documented. Although this does not exclude the possibility of such events, the potential risk, if any, is low. To report to the VARIVAX Pregnancy Registry, please call 1-800-986-8999 [9].

References

1. Epidemiology and Prevention of Vaccine-Preventable Diseases. Washington D.C.: Centers for Disease Control and Prevention; 2015.
2. Marin M, Guris D, Chaves SS, Schmid S, Seward JF. Prevention of varicella: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recommendations and reports : Morbidity and mortality weekly report Recommendations and reports 2007;56:1-40.
3. (AAP) AAoP. Neurodiagnostic evaluation of the child with a simple febrile seizure. Pediatrics 2011;127:389-94.
4. (AAP) AAoP. Febrile seizures: clinical practice guideline for the long-term management of the child with simple febrile seizures. Pediatrics 2008;121:1281-6.
5. Bonhoeffer J, Menkes J, Gold MS, et al. Generalized convulsive seizure as an adverse event following immunization: case definition and guidelines for data collection, analysis, and presentation. Vaccine 2004;22:557-62.
6. Tse A, Tseng HF, Greene SK, Vellozzi C, Lee GM. Signal identification and evaluation for risk of febrile seizures in children following trivalent inactivated influenza vaccine in the Vaccine Safety Datalink Project, 2010-2011. Vaccine 2012;30:2024-31.
7. Vaccine Information Statements (VIS). 2015, at http://www.cdc.gov/vaccines/hcp/vis/current-vis.html.)