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.
Keywords: Herpes zoster; postherpetic neuralgia; public health impact; recombinant zoster vaccine; vaccination.
In Hong Kong, the burden of shingles is increasing due to an aging population with increasing life expectancy. Vaccination can prevent shingles and reduce disease burden. Since 2021, two shingles vaccines are available in Hong Kong: zoster vaccine live (ZVL) and recombinant zoster vaccine (RZV). Using mathematical modeling, this study compared the public health impact (the number of cases of disease that would occur) of different shingles vaccination strategies, in a hypothetical population of 3.13 million Hong Kong adults aged ≥50 years in their remaining lifetime. The three strategies compared were no vaccination versus vaccination with ZVL or RZV. With no vaccination, public health burden of shingles would remain high, where an estimated 2 in 7 will have shingles, 1 in 20 will have shingles-related nerve pain, and 1 in 100 will have shingles around the eye. Vaccination (versus no vaccination) was predicted to reduce these cases by 47,477 (shingles), 7,701 (nerve pain), and 1,769 (shingles around the eye) for ZVL; and 204,875 (shingles), 31,949 (nerve pain), and 8,471 (shingles around the eye) for RZV. RZV avoided 4–5 times the number of cases compared with ZVL. Earlier RZV vaccination, from age 50 years, would have a greater public health impact than vaccination at a later age as the percentage of cases avoided with RZV (versus no vaccination) was highest in people aged 50–59 years compared with other age groups. These results may support value assessment and decision-making on public health vaccination strategies for shingles prevention in Hong Kong.