Vaccines: Varicella Zoster (Chickenpox and Shingles)

Authors’ note: We have chosen to present the vaccinations for chickenpox and shingles to highlight—and potentially correct—a common misconception. Both clinical syndromes in fact have the same causative agent: varicella-zoster virus. The names for chickenpox and shingles (the latter also called herpes zoster) are a historical holdover from an era when these were considered etiologically distinct entities. Also see Herpes Zoster, see Varicella.

There are also often misconceptions regarding why two separate vaccines are required for chickenpox and shingles. This is because immunosenescence causes a waning of the antibody response to varicella zoster with increasing age at the precise time when reactivation of the virus is most likely. Giving the live attenuated virus present in the chickenpox vaccine to the population at risk for shingles would result in a less durable antibody response in older patients, thus requiring a second recombinant protein-based vaccine to be used in the older population.

Specific vaccination recommendations vary among countries or even within a given country. Local or country-specific guidelines should be consulted.

Varicella (Chickenpox) VaccinationTop

1. Vaccine: Varicella vaccine contains live attenuated viruses. In North America, this is either available as a univalent vaccine or as a measles, mumps, rubella, and varicella (MMRV) vaccine, where these 4 are components of a single vaccine.

Varicella-zoster immunoglobulin is prepared from the antibodies of pooled human donors.

2. Indications: Varicella vaccination is recommended in all unvaccinated persons with a negative history of varicella.

3. Contraindications include general contraindications for all vaccines and specific contraindications for live vaccines. In addition, the vaccine is contraindicated in patients with a history of an anaphylactic reaction to neomycin, with active untreated tuberculosis, and in those who are pregnant. However, in cases of accidental varicella vaccination in pregnancy, termination of pregnancy should not be recommended.

While the measles and mumps components of the MMRV vaccine are produced in chick embryo cell culture, there appears to be an insufficient amount of egg protein to cause an allergic reaction in patients with egg allergy; for the purposes of patient safety, however, such an immunization should always be performed in a facility that can adequately manage this type of adverse events, should they arise.

There are several clinical instances where caution is necessary. Patients receiving systemic antiviral therapy should discontinue the therapy—if it is safe to do so—24 hours prior to vaccination until 14 days post vaccination. Tuberculin skin tests should be also avoided for 4 weeks after immunization with MMRV vaccines because of the risk of false-negative results. Salicylate therapy should be avoided for 6 weeks post varicella immunization due to the risk of Reye syndrome.

4. Immunization schedule: The primary vaccination series for healthy children from 12 months to 13 years of age includes 2 doses of either univalent varicella vaccine or MMRV vaccine, with the first dose administered at 12 to 15 months of age and the second dose administered at 18 months to no later than 4 years of age. Where the univalent varicella vaccine is used, it should be administered subcutaneously, whereas MMRV vaccines may be administered IM or subcutaneously.

In children aged <13 years old who did not receive varicella immunization as part of the routine childhood series, either univalent varicella or MMRV vaccines may be used, administered at 0 and 3 months. Seronegative adolescents aged 13 to 18 should receive 2 subcutaneous doses of univalent varicella vaccine at 0 and 6 weeks.

In the rare occurrence that adults are seronegative for varicella antibodies and do not have any contraindications to vaccination, they should be immunized with 2 doses of univalent varicella vaccine, administered subcutaneously, with ≥4 weeks between doses.

5. Postexposure prophylaxis should be considered after close contact with or significant exposure to a patient with varicella infection.

The following are considered significant exposures as a result of contact with a varicella-infected patient:

1) Living in the same household as a person with varicella.

2) Being indoors for ≥1 hour with a varicella-infected person.

3) ≥15 minutes of face-to-face contact with a person with varicella.

4) Contact with varicella lesions or the discharge from such lesions.

In susceptible, nonimmunocompromised, nonpregnant persons, univalent varicella vaccine should be given as postexposure prophylaxis within 72 hours of significant exposure. The input of an infectious disease physician should be sought for postexposure prophylaxis of immunocompromised or pregnant persons within 96 hours of exposure. In such cases, varicella-zoster immunoglobulin may be administered to prevent disease. Between 4 and 10 days after exposure varicella-zoster immunoglobulin may still be administered but the purpose of treatment is attenuation of severe disease as opposed to prevention, because of the unclear benefit of this intervention. Healthy infants <12 months of age do not require postexposure prophylaxis as they are thought to be protected by circulating maternal antibodies to varicella, provided that the infant’s mother is seropositive.

6. Adverse events: For the univalent varicella vaccine, transient pain and erythema at the injection site occur in 10% to 20% of vaccinated persons; in 3% to 5% of individuals a varicella-like rash may occur, in which case specimens should be obtained and sent to a reference public health laboratory to determine whether it is caused by a vaccine-derived varicella strain or a strain that is circulating in the community. Herpes zoster may rarely occur after univalent varicella vaccination.

Further discussion of adverse events specific to MMRV vaccines: see Vaccines: Measles, Mumps, and Rubella.

Herpes Zoster (Shingles) VaccinationTop

1. Vaccines: There are 2 formulations of shingles vaccination available: an adjuvanted recombinant vaccine (Shingrix) and a live attenuated vaccine (Zostavax II).

2. Indications: Vaccination with the recombinant vaccine is recommended for all patients ≥50 years of age without contraindications. Patients aged ≥50 years who have previously received the live attenuated shingles vaccine should be offered the 2-dose series of the recombinant vaccine; this recommendation is due to the significantly higher efficacy, immunogenicity, and durability of the immune response to the recombinant vaccine in older patients. The live attenuated vaccine is recommended only in cases where the recombinant vaccine is unavailable or contraindicated.

3. Contraindications include general contraindications for all vaccines and specific contraindications for live attenuated vaccines, if applicable. The use of the live attenuated vaccine is contraindicated in those with a history of a systemic anaphylactic reaction to neomycin or porcine gelatin and in pregnant patients. Patients receiving the live attenuated vaccine should be counseled to avoid pregnancy for 3 months following its administration. Notably, the live attenuated vaccine is not contraindicated in those receiving topical, inhaled, or low-dose glucocorticoids. Caution should be exercised in breastfeeding patients receiving the live attenuated vaccine as the potential for viral transmission in breast milk is poorly understood.

4. Immunization schedule: Where the recombinant vaccine is used (in most clinical scenarios), the primary series includes 2 doses administered IM in the deltoid muscle at 0 and 2 to 6 months. Where the live attenuated vaccine is used, the primary series consists of 1 dose administered subcutaneously.

5. Postexposure prophylaxis: In susceptible persons exposed to shingles after close contact with a patient, shingles vaccines should not be used; instead, use univalent varicella vaccines for postexposure prophylaxis in patients without contraindications.

The following are considered significant exposures to shingles:

1) Living in the same household as an immunocompromised patient with shingles, or a patient with disseminated shingles prior to or within 24 hours of initiating antiviral therapy.

2) Being indoors for ≥1 hour with an immunocompromised patient with shingles, or a patient with disseminated shingles prior to or within 24 hours of initiating antiviral therapy.

3) ≥15 minutes of face-to-face contact with an immunocompromised patient with shingles, or a patient with disseminated shingles prior to or within 24 hours of initiating antiviral therapy.

4) Contact with shingles lesions or the discharge from such lesions.

In susceptible, nonimmunocompromised, nonpregnant persons, univalent varicella vaccine should be given as postexposure prophylaxis within 72 hours of significant exposure. The input of an infectious disease physician should be sought for postexposure prophylaxis of immunocompromised or pregnant persons within 96 hours of exposure. In such cases, varicella-zoster immunoglobulin may be administered to prevent disease. Between 4 and 10 days after exposure varicella-zoster immunoglobulin may still be administered but the purpose of treatment is attenuation of severe disease as opposed to prevention, because of the unclear benefit of this intervention. Healthy infants <12 months of age do not require postexposure prophylaxis as they are thought to be protected by circulating maternal antibodies to varicella, provided that the infant’s mother is seropositive.

6. Adverse events: Transient pain (>80%) and transient erythema (>30%) at the injection site. In the case of the recombinant vaccine, transient headache and fatigue typically occur in up to half of recipients for 2 to 3 days; counseling patients to expect such transient adverse effects will promote adherence to further doses. Case reports of reactivation of herpes zoster ophthalmicus have been noted following the administration of the live attenuated vaccine; however, a causal relationship has yet to be definitively established.