Abstract
Herpes zoster (HZ) and HZ-associated pain greatly affect patients' quality of life, particularly in older and immunocompromised adults, for whom comorbidities and polypharmacy are often reported. Three phase III, randomized, placebo-controlled clinical trials have reported the adjuvanted recombinant zoster vaccine (RZV) as highly efficacious in preventing HZ and reducing pain severity in healthy adults ≥50 years old (Zoster Efficacy Study [ZOE]-50 study, NCT01165177) and ≥70 years old (ZOE-70; NCT01165229) and in immunocompromised adults ≥18 years old undergoing autologous hematopoietic stem cell transplantation (ZOE-HSCT; NCT01610414). Here, we investigated efficacy of RZV in reducing (i) the duration of clinically significant pain (Zoster Brief Pain Inventory pain score ≥3) and (ii) HZ-associated pain medication use and duration of use in participants with confirmed HZ ("breakthrough cases") from the 3 studies. Recombinant zoster vaccine effectively reduced the duration of clinically significant HZ-associated pain during HZ episodes by 38.5% ( P -value: 0.010) in the ZOE-HSCT study. Although a similar trend was observed in the ZOE-50 and ZOE-70 studies, the results were not statistically significant because of the high vaccine efficacy (VE) against HZ resulting in rare breakthrough cases. VE in reducing pain medication use (39.6%; P -value: 0.008) and duration of medication use (49.3%, P -value: 0.040) was reported in the ZOE-70 study; corresponding positive VE estimates were observed in the ZOE-50 and ZOE-HSCT studies but were not statistically significant. Data reported here demonstrate efficacy of RZV in reducing HZ-associated pain duration and pain medication use in breakthrough cases, thereby improving quality of life of those with HZ.