Postmarketing safety study of polymyalgia rheumatica and giant cell arteritis following exposure to the recombinant zoster vaccine in adults ≥50 in the United States

Purpose Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) are related inflammatory conditions primarily impacting older adults. Clinical trials of the recombinant zoster vaccine (RZV) identified more PMR and GCA cases in the RZV than placebo arms. This study was conducted to characterize real-world risks of PMR and GCA in adults aged ≥50 after RZV. Methods This study was conducted using claims data from five U.S. Research Partners. RZV Dose 1 or 2 could serve as the index date. Unvaccinated comparators were identified at a randomly selected preventive healthcare visit, with further random sampling to achieve a 1:4 ratio. PMR and GCA were identified from claims in the 183 days following RZV. Inverse-probability-of-treatment weighting (IPTW) was used for confounding control. We described pre-index characteristics for the analytic cohorts before and after IPTW and estimated crude and IPTW hazard ratios (HRs). Results 300,666 RZV recipients and 1,159,359 comparators were included in the PMR analytic cohorts. The Dose 1 and 2 IPTW HRs were 0.66 (95% CI: 0.53, 0.80) and 0.54 (95% CI: 0.40, 0.71), respectively. Secondary and sensitivity analyses were generally consistent with primary analyses. 640,398 RZV recipients and 2,515,736 comparators were included in the GCA analysis. The Dose 1 and 2 IPTW HRs for chart-confirmed GCA were 1.67 (95% CI: 0.63, 4.46) and 3.11 (95% CI: 1.23, 7.90), respectively. Results of additional analyses were variable. Conclusions This study did not find any evidence of increased risk of PMR following RZV in older U.S. adults. Analyses of GCA produced inconsistent findings.