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.
Safety and effectiveness of the herpes zoster vaccine to prevent postherpetic neuralgia: 2014 Update and consensus statement from the Canadian Pain Society
