Public health impact of herpes zoster vaccination on older adults in Hong Kong

Abstract

The growing burden of herpes zoster (HZ) in Hong Kong, due to an aging population with increasing life expectancy, may be reduced by vaccination. This study aimed to estimate public health impact of HZ vaccination in Hong Kong. The ZOster ecoNomic Analysis (ZONA) model was adapted with Hong Kong-specific key model inputs/assumptions, where available. Base case analysis involved adults ≥50 years of age (YOA), exploring three vaccination strategies (no vaccination/recombinant zoster vaccine [RZV]/zoster vaccine live [ZVL]) under private market (5% coverage) and mass vaccination (40% coverage) settings. Scenario and sensitivity analyses were performed. In the base case population (3.13 million), without vaccination, 891,024 HZ (28.4%), 156,097 post-herpetic neuralgia (PHN) (5.0%), and 38,755 (1.2%) HZ ophthalmicus (HZO) were projected over their remaining lifetime. Mass RZV vaccination reduced HZ, PHN, and HZO cases by 204,875 (−23.0%), 31,949 (−20.5%), and 8,471 (−21.9%), respectively, which was 4–5 times that reduced with ZVL. RZV was more efficient than ZVL, with lower number needed to vaccinate to prevent one HZ/PHN/HZO case (RZV: 7/40/148; ZVL: 27/163/709). Among all age cohorts, the greatest reduction in cases was projected for RZV (versus no vaccination/ZVL) in the youngest cohort, 50–59 YOA. Results were robust under scenario and sensitivity analyses. HZ burden in Hong Kong is substantial. Mass RZV vaccination is expected to considerably reduce public health burden of HZ among individuals ≥50 YOA, compared with no vaccination/ZVL. Results may support value assessment and decision-making regarding vaccination strategies for HZ prevention in Hong Kong.

Public health impact of herpes zoster vaccination on older adults in Singapore: a modeling study

“…These NNV results are comparable to those from PHI analyses of RZV in Beijing, and of RZV and ZVL in Hong Kong. 47 , 48 NNV was not previously reported in the published cost-effectiveness analysis of ZVL in Singapore. 71 …”

“…The NNV with RZV to prevent HZ increased with age, from 6 in the 50–59 YOA cohort to 15 in the ≥ 80 YOA cohort, while the NNV to prevent PHN decreased from 41 in the 50–59 YOA cohort to 35 in the 60–64 YOA cohort and then increased to 55 in the ≥ 80 YOA cohort; these trends in the NNV with RZV in Singapore were similar to those reported for Hong Kong. 47 For HZ, the increase in NNV with age would mainly be due to the combined effect of lower initial vaccine efficacy, greater waning of vaccine efficacy, and shorter follow-up period in older adults. On the other hand, the drop in NNV for PHN in the 60–64 YOA cohort was due to the greater burden of PHN at 60 YOA compared to 50 YOA, while its subsequent increase with age was due to increased vaccine efficacy against PHN at 60 YOA compared to 70 YOA.…”

“…82 , 83 Additionally, published PHI models of RZV, in majority Chinese populations of Hong Kong and Beijing, also used similar second-dose compliance rates (80.0–82.5%). 47 , 48 …”