Recombinant Herpes Zoster Vaccine for Elderly Patients with Prior Chickenpox
An elderly patient who had chickenpox as a child needs the recombinant herpes zoster vaccine (RZV), not the varicella vaccine. The varicella vaccine is for preventing primary chickenpox infection, while the recombinant zoster vaccine prevents shingles (herpes zoster), which is the reactivation of the latent varicella-zoster virus that remains dormant after the initial chickenpox infection 1.
Why Recombinant Zoster Vaccine (RZV) is Indicated
The CDC Advisory Committee on Immunization Practices strongly recommends RZV for all immunocompetent adults aged 50 years or older for prevention of herpes zoster and its complications 1, 2. This recommendation applies regardless of whether the patient had natural chickenpox or previous varicella vaccination 1.
Key Supporting Evidence:
After primary varicella infection (chickenpox), the virus establishes latency in neuronal ganglia and can reactivate later in life to cause herpes zoster (shingles) 1. Approximately 20-30% of people will develop herpes zoster over their lifetime, with incidence increasing markedly beginning at approximately 50 years of age 1.
RZV is preferred over the older live zoster vaccine (ZVL) due to superior efficacy: 96% versus 70% 1, 3. Real-world effectiveness studies confirm RZV effectiveness at 85% compared to 46% for ZVL 4.
RZV efficacy exceeds 90% against herpes zoster and is sustained over multiple years in all age groups studied 5. In adults aged 70+ years, efficacy remains ≥89% against post-herpetic neuralgia (PHN), the most debilitating complication 5.
Why NOT Varicella Vaccine
The varicella vaccine is designed to prevent primary chickenpox infection in those who have never had the disease 1. Since your patient already had chickenpox as a child, they have established immunity to primary varicella infection and do not need varicella vaccination 1.
In the prevaccine era, 97-99% of adults with a positive history of varicella were seropositive, and data indicate that 95.5% of people 20-29 years old, 98.9% of people 30-39 years old, and 99.6% of people 40+ years had immunity to VZV 1.
Varicella vaccine contains live-attenuated virus and is indicated for people 12 months and older who have NOT had chickenpox 1.
Practical Implementation
Administer RZV as a two-dose series 2, 3:
- The recombinant vaccine requires two doses for optimal protection 5
- RZV is safe for immunocompromised patients (unlike the live ZVL) because it is non-replicating 6, 3
Important Considerations:
Patients who previously received the older live zoster vaccine (ZVL/Zostavax) should still receive RZV for better protection 1, 3
For patients on immunosuppressive therapy (including JAK inhibitors, biologics, or corticosteroids ≥20 mg/day prednisolone equivalent), RZV should ideally be given before starting therapy or can be safely administered during therapy since it is non-live 1, 3
Common side effects include injection-site reactions and systemic symptoms (fatigue, myalgia, headache, fever), which are generally mild to moderate and temporary 3, 4. Despite higher reactogenicity compared to placebo, there is no significant difference in serious adverse events 3.
Clinical Pitfall to Avoid
Do not confuse the indication for varicella vaccine (preventing primary chickenpox) with herpes zoster vaccine (preventing shingles reactivation) 1. A common error is thinking that someone who had chickenpox decades ago might need a "booster" of varicella vaccine—this is incorrect. The appropriate intervention is herpes zoster vaccination to prevent reactivation disease 1, 2.