Abstract
Background
Shingrix™ (recombinant zoster vaccine) was licensed to prevent herpes zoster, dispensed as two doses given 2–6 months apart, among adults ages ≥50 years. Clinical trials yielded efficacy of >90% for confirmed herpes zoster,but post-market vaccine performance has not been evaluated. Efficacy of a single dose, delayed second dose, or among persons with autoimmune or general immunosuppressive conditions have also not been studied. We aimed to assess post-market vaccine effectiveness of Shingrix.
Methods
We conducted a cohort study among vaccinated and unvaccinated Medicare Part D community dwelling beneficiaries ages >65 years. Herpes zoster was identified using a medical office visit diagnosis with treatment, and postherpetic neuralgia 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% CI, 68.6–71.5) and 56.9% (95% CI, 55.0–58.8) for two and one doses, respectively. The two-dose vaccine effectiveness was not significantly lower for beneficiaries 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 effectiveness of Shingrix demonstrates the benefit of completing the two-dose regimen. Second doses administered beyond the recommended 6 months did not impair vaccine effectiveness.Our effectiveness estimates were lower than the clinical trials estimates, likely due to differences in outcome specificity.
Zoster vaccine (Zostavax®): a guide to its use in preventing herpes zoster and postherpetic neuralgia
