Two-dose recombinant shingles vaccine effective, even in patients who got live version
Two doses of the recombinant vaccine had a relative effectiveness of 67.9% versus one dose, and the second dose was similarly effective whether administered within the CDC-recommended interval of two to six months after the first or within an extended window.
Patients vaccinated with live zoster vaccine should be revaccinated with two doses of recombinant zoster vaccine, according to the results of a new study.
Researchers did a target trial emulation to assess the effectiveness of the recombinant zoster vaccine in patients who received the live one, by analyzing a 20% random sample of Medicare beneficiaries ages 65 years or older between 2007 and 2019. Participants had to have six months of continuous Medicare coverage before trial enrollment, no claims for herpes zoster since 2007, and no prior receipt of the recombinant vaccine. Outcomes were herpes zoster infection, related ophthalmicus, and postherpetic neuralgia. Covariates were age, sex, race, ethnicity, prior receipt of live vaccine, and immunocompetence. The study was published Oct. 14 by Annals of Internal Medicine.
Among 3,456,555 patients in 12 emulated trials, the one-year vaccine effectiveness of at least one dose of the recombinant vaccine was 56.1% (95% CI, 53.1% to 59.0%) against any of the outcomes. Effectiveness was similar among individuals ages 65 to 80 years and among immunocompromised and immunocompetent individuals. Effectiveness was 51.8% (95% CI, 44.7% to 57.9%) among individuals who had previously received the live vaccine compared with 57.7% (95% CI, 54.2% to 60.9%) among those who had not.
In a second analysis, 146,296 individuals were evaluated across 10 emulated trials to determine the effectiveness of two doses of the recombinant vaccine versus one. Two doses yielded a relative effectiveness of 67.9% (95% CI, 64.2% to 71.3%) against any of the studied outcomes compared with one dose. Additionally, the analysis found that the second dose was similarly effective whether it was administered within the CDC-recommended interval of two to six months after the first or within an extended window, a finding that emphasizes the importance of completing the full vaccination series even in the event of delays, the study authors said.
“Our study of more than 3 million Medicare enrollees found that RZV [the recombinant vaccine] was effective under real-world conditions,” they wrote. “Our analysis showed that those who have previously received [the live vaccine] benefit from RZV and should be revaccinated.”