In a patient with no documented history of chickenpox and no varicella antibody titer, should I give the live‑attenuated varicella (chickenpox) vaccine, the recombinant zoster (shingles) vaccine, or both?

Varicella Vaccine Recommendation for Seronegative Adults

Give the varicella (chickenpox) vaccine—not the shingles vaccine—to patients without documented chickenpox history and no varicella antibody titer, using a 2-dose series separated by 4 weeks. 1, 2

Understanding the Clinical Context

The absence of chickenpox history does not automatically mean VZV seronegativity—88-91% of adults have been exposed to varicella-zoster virus even without recalled chickenpox, indicating subclinical or forgotten childhood infection. 1 However, when you have confirmed absence of varicella antibodies (no titer), this patient is truly VZV-seronegative and requires primary immunization, not zoster prevention. 1

Why Varicella Vaccine, Not Shingles Vaccine

Primary Immunization is the Priority

• Truly VZV-seronegative individuals have essentially zero risk of herpes zoster because you cannot reactivate a virus you've never been infected with. 1
• The shingles vaccine (Shingrix) is designed to boost existing immunity from prior VZV exposure, not to provide primary immunization against varicella. 3, 4
• Shingrix is not indicated for prevention of primary varicella infection (chickenpox). 4

Age-Based Vaccination Guidelines

• For immunocompetent adults under age 50: No routine herpes zoster vaccination is recommended, as standard zoster vaccines (both live zoster vaccine and recombinant zoster vaccine) are approved for ages 50 and older. 1
• For immunocompetent adults age 50 and older: After completing the varicella vaccine series, they should subsequently receive Shingrix for zoster prevention. 1, 3
• For immunocompromised adults age 18-49: Consider Shingrix regardless of chickenpox history, but only after establishing primary immunity with varicella vaccine if seronegative. 1, 3

Varicella Vaccination Protocol

Dosing Schedule

• Administer 2 doses of single-antigen varicella vaccine at least 4 weeks apart. 1, 2
• The vaccine is a live attenuated vaccine, so screen for contraindications before administration. 2

Key Contraindications and Precautions

• Defer vaccination in individuals with family history of congenital or hereditary immunodeficiency until immune status is evaluated. 2
• Live varicella vaccine is contraindicated in HIV-infected adults and children due to risk of disseminated viral infection. 5
• Avoid salicylates (aspirin) for 6 weeks following vaccination in children and adolescents due to Reye syndrome risk. 2
• Do not administer immune globulins or blood products concomitantly as they may interfere with vaccine virus replication. 2

Post-Vaccination Transmission Risk

• Vaccine recipients should avoid close contact with high-risk susceptible individuals for up to 6 weeks following vaccination, as transmission of vaccine virus can occur even without a varicella-like rash. 2
• High-risk individuals include immunocompromised persons, pregnant women without varicella immunity, and newborn infants. 2

Critical Pitfalls to Avoid

Serologic Testing Limitations

• Commercial ELISA assays were designed to measure higher titers from natural infection, not the lower titers induced by vaccination. 6
• If post-vaccination titers appear negative on standard ELISA, consider more sensitive assays (fluorescent antibody to membrane antigen or latex agglutination) before re-vaccinating. 6
• Some individuals may have adequate cell-mediated immunity despite low antibody titers on commercial assays. 6

Don't Assume Immunity Without Documentation

• Individuals with negative or uncertain chickenpox history should undergo serological testing before assuming susceptibility. 7
• Those with a definite history of VZV infection can be considered immune without testing. 7

Special Population Considerations

• For healthcare workers: Serological testing and immunization of nonimmune individuals is recommended to prevent nosocomial transmission of VZV. 7
• For HIV-infected individuals: Consult ACIP recommendations, as live varicella vaccine is generally contraindicated. 5, 2

Subsequent Zoster Vaccination

Once primary varicella immunity is established:

• Adults age 50 and older should receive Shingrix (2 doses, typically 2-6 months apart, though can be given as early as 4 weeks if early protection is desired). 3
• Shingrix remains immunogenic and effective even in those who received varicella vaccination rather than having natural chickenpox. 3
• The recombinant zoster vaccine is not live and is safe for immunocompromised patients. 3, 4