Recombinant Zoster Vaccine (Shingrix): Real-World Effectiveness in the First 2 Years Post-Licensure

Background. Shingrix (recombinant zoster vaccine) was licensed to prevent herpes zoster, dispensed as 2 doses given 2-6 months apart among adults aged >= 50 years. Clinical trials yielded efficacy of >90% for confirmed herpes zoster, but post-market performance has not been evaluated. Efficacy of a single dose and a delayed second dose and efficacy among persons with autoimmune or immunosuppressive conditions have not been studied. We aimed to assess post-market vaccine effectiveness of Shingrix. Methods. We conducted a cohort study among Medicare Part D community-dwelling beneficiaries aged >65 years. Herpes zoster was identified using a medical office visit diagnosis with treatment, and postherpetic neuralgia was identified using a validated algorithm. We used inverse probability of treatment weighting to improve cohort balance and marginal structural models to estimate hazard ratios. Results. We found a vaccine effectiveness of 70.1% (95% confidence interval [CI], 68.6-71.5) and 56.9% (95% CI, 55.0-58.8) for 2 and 1 doses, respectively. The 2-dose vaccine effectiveness was not significantly lower for beneficiaries aged >80 years, for second doses received at >= 180 days, or for individuals with autoimmune conditions. The vaccine was also effective among individuals with immunosuppressive conditions. Two-dose vaccine effectiveness against postherpetic neuralgia was 76.0% (95% CI, 68.4-81.8). Conclusions. This large real-world observational study of the effectiveness of Shingrix demonstrates the benefit of completing the 2-dose regimen. Second doses administered beyond the recommended 6 months did not impair effectiveness. Our effectiveness estimates were lower than the clinical trials estimates, likely due to differences in outcome specificity.

Automated summary

This study evaluated the post-market effectiveness of the Shingrix vaccine and found vaccine effectiveness of 70.1% and 56.9% for 2 doses and 1 dose, respectively. The effectiveness of the 2-dose vaccine did not significantly decrease for beneficiaries aged over 80, for delays in receiving the second dose, or for individuals with autoimmune conditions. The vaccine also showed effectiveness among individuals with immunosuppressive conditions.