Varicella Vaccine

measles, mumps, rubella (MMRV).

Varicella vaccine is a routine childhood vaccine (see CDC: Child and Adolescent Immunization Schedule by Age).

Single-antigen varicella vaccine also is recommended for all people ≥ 13 years who do not have evidence of immunity to varicella (see CDC: Adult Immunization Schedule by Age.)

Evidence of immunity consists of one of the following:

• Documentation of 2 doses of varicella vaccine given ≥ 4 weeks apart

• History of varicella or herpes zoster verified by a health care professional

• Laboratory confirmation of protective levels of varicella antibodies

• Birth in the United States before 1980, except for health care workers and pregnant women

The varicella vaccine is recommended particularly for people who do not have evidence of immunity and are likely to be exposed to or transmit varicella, including the following:

• Health care workers

• Household contacts of immunocompromised people

• People who live or work in places where exposure or transmission is likely (eg, teachers, students, child care workers, residents and employes of institutional settings, inmates and employees of correctional institutions, military personnel)

• Women of childbearing age who are not pregnant

• Adolescents and adults living in households with children

• International travelers

Postexposure vaccination with the single-antigen varicella vaccine is recommended for children with no evidence of immunity and should be offered to adults with no evidence of immunity. The vaccine is effective in preventing or ameliorating disease if it is given within 3 days and possibly up to 5 days after exposure; however, the vaccine should be given as soon as possible. If exposure to varicella does not cause infection, postexposure vaccination should induce protection against subsequent exposures, even if the vaccine is given > 5 days postexposure.

(see table Immune Globulins and Antitoxins Available in the United States) is recommended for postexposure prophylaxis in people who have no evidence of immunity, are at increased risk of severe varicella, and/or have contraindications to the varicella vaccine. These people include

• Immunocompromised people without evidence of immunity

• Pregnant women without evidence of immunity

• Neonates whose mothers developed varicella within 5 days before to 2 days after delivery

• Hospitalized premature infants who were born at ≥ 28 weeks gestation and whose mothers do not have evidence of immunity to varicella

• Hospitalized premature infants who were born at < 28 weeks gestation or who weigh ≤ 1000 g at birth, regardless of their mother's evidence of immunity to varicella

Contraindications for varicella vaccine include

• A severe allergic reaction (eg, anaphylaxis) after a previous dose of the vaccine or to a vaccine component

• Known severe primary or acquired immunodeficiency (eg, due to leukemia, lymphomas, solid tumors, tumors that affect bone marrow or the lymphatic system, AIDS, severe HIV infection, treatment with chemotherapy, or long-term use of immunosuppressants)

• Unless people are known to be immunocompetent, family history of first-degree relatives who have congenital hereditary immunodeficiency

• Confirmed or suspected pregnancy

The single-antigen varicella vaccine may be given to children aged 1 to 8 years who have HIV infection if their CD4 percentage is ≥ 15; it may be given to those > 8 years if their CD4 percentage is ≥ 15 and CD4 count is ≥ 200/mcL with no evidence of immunity.

Precautions with varicella vaccine include

• Moderate or severe acute illness with or without fever (vaccination is postponed until illness resolves)

• Recent (within 11 months) treatment with blood products that contain antibody (specific interval depends on the product)

Breastfeeding is not a contraindication to vaccination. Women who are breastfeeding and do not have evidence of immunity can be vaccinated postpartum and continue breastfeeding.

The varicella vaccine dose is 0.5 mL given subcutaneously in 2 doses: at age 12 to 15 months and at age 4 to 6 years. If children, adolescents, or adults have been given only 1 dose, a catch-up dose is recommended. The recommended minimum interval between the first dose and the catch-up second dose is 3 months for children aged ≤ 12 years and 4 weeks for people aged ≥ 13 years; the second dose may be given at any interval longer than the minimum.

If adults think that they have not had varicella or are likely to be exposed to or to transmit varicella, levels of protective antibodies should be measured to check for evidence of immunity and thus determine the need for vaccination.

Eligible children with HIV infection are given 2 doses of single-antigen varicella vaccine 3 months apart. Because impaired cellular immunity increases the risk of complications after vaccination with a live vaccine, these children should be encouraged to return for evaluation if a varicella-like rash develops after vaccination.

Prenatal assessment of women for evidence of varicella immunity is indicated. Birth before 1980 is not considered evidence of immunity for pregnant women. After completion or termination of pregnancy, women who do not have evidence of immunity should be given the first dose of vaccine before discharge and the second dose 4 to 8 weeks later, usually at the postpartum visit. Women should be advised to avoid becoming pregnant for 1 month after each dose.

Most adverse effects are minimal and include transient pain, tenderness, and redness at the injection site. Occasionally, within 1 month of vaccination, a mild maculopapular or varicella-like rash develops in 1 to 3% of people who are vaccinated. Vaccine recipients who develop this rash should diligently avoid contact with immunocompromised people until it resolves. Spread of the virus from vaccine recipients to susceptible people is rare but can result in severe problems, including pneumonia, hepatitis, severe rash, and shingles with meningitis. However, such problems rarely develop.

Because Reye syndrome can develop, recipients < 16 years should avoid salicylates for 6 weeks after the vaccine is given.

The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

1. Advisory Committee on Immunization Practices (ACIP): Varicella ACIP Vaccine Recommendations

2. Centers for Disease Control and Prevention (CDC): Varicella Vaccination: Information for Healthcare Professionals

3. European Centre for Disease Prevention and Control (ECDC): Varicella: Recommended vaccinations