Two-Dose Recombinant Zoster Vaccine Effective in Older Adults, Regardless of Prior Vaccination

MONDAY, Oct. 20, 2025 (HealthDay News) — Two doses of the recombinant zoster vaccine (RZV) are effective in older adults, including immunocompromised adults, according to a study published online Oct. 13 in the Annals of Internal Medicine.

Nadja A. Vielot, Ph.D., from the University of North Carolina at Chapel Hill, and colleagues examined RZV effectiveness using target trial emulation, accounting for prior receipt of a live zoster vaccine (ZVL) and immunocompetence. Analysis 1 assessed 12 sequential trials of at least 12 months” duration. Pooled vaccine effectiveness was estimated across the trials. The same method was used in analysis 2 to estimate vaccine effectiveness of two RZV doses versus one dose, with 10 trials starting 60 days from the first dose. Participants were Medicare beneficiaries aged 65 years or older with continuous Part D coverage, with no prior RZV vaccination.

The researchers found that vaccine effectiveness was 56.1 percent against any herpes zoster (HZ) outcome, with similar vaccine effectiveness for immunocompetent and immunocompromised individuals (56.5 versus 54.2 percent). Benefit was seen from RZV for individuals vaccinated with ZVL in the past 10 years. An additional 67.9 percent effectiveness against any HZ outcome was conferred by a second RZV dose.

“The second dose is similarly effective whether it is administered within the CDC (U.S. Centers for Disease Control and Prevention)-recommended window or within an extended window after the first dose, emphasizing the importance of completing the full vaccination series even in the event of delays,” the authors write.

Several authors disclosed financial ties to the pharmaceutical industry.

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