Paola Pirrotta, Juan Carlos Tinoco, Isabelle Schenkenberger, Tino F. Schwarz, Huey-Shinn Cheng, Céline Boutry, Meral Esen, Charles P. Andrews, Beate Moeckesch, Andrew Hastie, Pavel Kosina, Chong-Jen Yu, Thiago Junqueira Avelino-Silva, Javier Díez-Domingo, Lars Rombo, Shinn-Jang Hwang, Johan Berglund, Dan Curiac, Jean Beytout, Anne Schuind, Bruno Salaun, Tamara Eckermann, Karlis Pauksens, Dae Won Park, Marc Dionne, Toufik Zahaf, Carol Pretswell, Jukka Markkula, Cláudia Murta de Oliveira, Georg Plassmann, Meng Shi, Benita Ukkonen, Emmanuel Di Paolo, Hee Jin Cheong, Murdo Ferguson, Chiu-Shong Liu, Covadonga Caso, Anthony L. Cunningham, Eun Ju Choo, Wayne Ghesquiere, Cristiano Zerbini, Tampere University, and Clinical Medicine
Background This ongoing follow-up study evaluated the persistence of efficacy and immune responses for 6 additional years in adults vaccinated with the glycoprotein E (gE)-based adjuvanted recombinant zoster vaccine (RZV) at age ≥50 years in 2 pivotal efficacy trials (ZOE-50 and ZOE-70). The present interim analysis was performed after ≥2 additional years of follow-up (between 5.1 and 7.1 years [mean] post-vaccination) and includes partial data for year (Y) 8 post-vaccination. Methods Annual assessments were performed for efficacy against herpes zoster (HZ) from Y6 post-vaccination and for anti-gE antibody concentrations and gE-specific CD4[2+] T-cell (expressing ≥2 of 4 assessed activation markers) frequencies from Y5 post-vaccination. Results Of 7413 participants enrolled for the long-term efficacy assessment, 7277 (mean age at vaccination, 67.2 years), 813, and 108 were included in the cohorts evaluating efficacy, humoral immune responses, and cell-mediated immune responses, respectively. Efficacy of RZV against HZ through this interim analysis was 84.0% (95% confidence interval [CI], 75.9–89.8) from the start of this follow-up study and 90.9% (95% CI, 88.2–93.2) from vaccination in ZOE-50/70. Annual vaccine efficacy estimates were >84% for each year since vaccination and remained stable through this interim analysis. Anti-gE antibody geometric mean concentrations and median frequencies of gE-specific CD4[2+] T cells reached a plateau at approximately 6-fold above pre-vaccination levels. Conclusions Efficacy against HZ and immune responses to RZV remained high, suggesting that the clinical benefit of RZV in older adults is sustained for at least 7 years post-vaccination. Clinical Trials Registration. NCT02723773.