Modelling the Public Health Burden of Herpes Zoster and the Impact of Adjuvanted Recombinant Zoster Vaccine in Five Selected Countries in Southeast Asia.

INTRODUCTION: Herpes zoster (HZ) can cause substantial patient morbidity and lead to large healthcare costs. However, the disease burden of HZ in Southeast Asia may be underestimated. This study aimed to estimate the public health burden of HZ and the impact of vaccinating adults aged ≥ 50 years old in five Southeast Asian countries (Indonesia, Malaysia, Philippines, Thailand, and Vietnam), with adjuvanted recombinant zoster vaccine (RZV) compared with no vaccination. METHODS: For each country, we adapted a static multicohort Markov model developed with a 1-year cycle length and lifetime horizon. Demographics were obtained from the World Health Organization, HZ incidence from a worldwide meta-regression reporting Asian-specific values, proportions of postherpetic neuralgia (PHN) and non-PHN complications from local/regional studies, and vaccine efficacy from a long-term follow-up trial. First-dose coverage and second-dose compliance were assumed to be 30% and 70%, respectively. A one-way deterministic sensitivity analysis (OWSA) and probabilistic sensitivity analysis (PSA) were performed to assess the robustness and uncertainty of inputs for each country. RESULTS: Without RZV, it was estimated that there would be a total of approximately 10 million HZ cases, 2.1 million PHN cases, and 1.4 million non-PHN complications in individuals aged ≥ 50 years included in the model. Introducing RZV under 30% coverage could avoid approximately 2.2 million (22%) HZ cases, almost 500,000 (21%) PHN cases, and around 300,000 (22%) non-PHN complications. OWSA showed that first-dose coverage and initial HZ incidence had the largest impact on the estimated number of HZ cases avoided. The number needed to vaccinate ranged from 15 to 21 to prevent one case of HZ and from 68 to 104 to prevent one case of PHN across each country. CONCLUSIONS: This study demonstrated that there is substantial HZ disease burden in older adults for the five selected countries in Southeast Asia, negatively impacting national healthcare systems. Introducing RZV could potentially reduce this burden. A graphical abstract is available with this article.

How large could the public health impact of introducing recombinant zoster vaccination for people aged ≥50 years in five Latin American countries be?

This study aimed to: (1) estimate the disease burden of herpes zoster (HZ) and (2) assess the potential public health impact of introducing adjuvanted recombinant zoster vaccine (RZV) compared with no vaccination in adults aged ≥50 years in Argentina, Brazil, Mexico, Chile, and Colombia using the ZOster ecoNomic Analysis (ZONA) static multicohort Markov model. The model followed individuals aged ≥50 years from administration of RZV over their remaining lifetime. Inputs were based, most often, on local data. First dose coverage was assumed to be 35%, with 75% second dose compliance. It was predicted that without RZV, there would be 23,558,675 HZ cases, 6,115,981 post-herpetic neuralgia (PHN) cases, and 7,058,779 non-PHN complications in the five countries, but introducing RZV under assumed coverage could avoid 4,583,787 (19%) HZ cases, 1,130,751 (18%) PHN cases, and 1,373,419 (19%) non-PHN complications. Also, 10427,504 (20%) doctor's office visits and 1,630,201 (19%) days of hospitalization could be averted in the three countries (Argentina, Brazil, and Mexico) with available input data. The numbers needed to be vaccinated to avoid one case of HZ were 9-10 across countries, and to avoid one case of PHN, 35-40. One-way sensitivity analyses showed that the input parameters with the largest impact on the estimated number of HZ cases avoided were first dose coverage, initial HZ incidence, and vaccine efficacy waning. In conclusion, the introduction of RZV for older adults in Latin America could greatly reduce the public health burden of HZ and reduce the related doctor visits and hospitalization days.

Why was the study done?Herpes zoster (HZ), commonly known as shingles or "culebrilla," typically causes a painful, itchy rash on the trunk in older adults, and can result in long-term complications. It is difficult to study the lifetime burden of HZ due to follow-up time constraints. We therefore wanted to predict how many people could develop HZ as they age and how many cases of HZ could be avoided by introducing adjuvanted recombinant zoster vaccine (RZV) in people aged 50 years and older in five Latin American countries (Argentina, Brazil, Mexico, Chile, and Colombia).What did the researchers do and find?Using a mathematical model, we predicted that nearly 5 million of an estimated 24 million cases of HZ could be avoided by vaccinating 35% of older adults with RZV in the five countries. This vaccination approach would also avert various complications of HZ, including post-herpetic neuralgia (long-lasting pain at the rash site) and save doctor's office visits and hospitalizations for HZ.What do the results mean?Introducing RZV for older adults in Latin America ­ as is already the case in various other countries ­ could prevent a substantial proportion of HZ cases, leading to improved public health and less health care resource utilization.What is the objective influence on the wider field?In the absence of real-world data on the potential impact of RZV on HZ in Latin America, these predictions could help policymakers to assess the potential value of introducing RZV for older adults in Latin America.

Public health impact model estimating the impact of introducing an adjuvanted recombinant zoster vaccine into the UK universal mass vaccination programme.

OBJECTIVES: In 2013, the herpes zoster (HZ) immunisation programme was introduced in the UK, recommending vaccination of adults 70 years of age (YOA) with the zoster vaccine live (ZVL), the only vaccine available at the time. The recently approved adjuvanted recombinant zoster vaccine (RZV) has a substantially different clinical profile that may offer additional benefits.This study aimed to 1) assess the public health impact (PHI) of introducing RZV in the UK compared with the current vaccination strategy and 2) explore via scenario analyses the optimal age group of vaccination in terms of PHI. DESIGN: A previously developed health economic model was adapted to the UK setting. SETTING: Calculations were based on efficacy data from pivotal clinical trials, HZ incidence and postherpetic neuralgia (PHN) probability from a UK study and HZ-associated complication rates from published literature. POPULATION: The base-case population considered a 2018-projected UK vaccination cohort of individuals 70 YOA. INTERVENTIONS: Vaccination with ZVL or RZV, assuming a first-dose coverage of 48.3% for both vaccines and 70% compliance for the second dose of RZV. OUTCOME MEASURES: Outcomes included reduction of HZ and PHN cases, complications and the use of healthcare resources over a life-time horizon. The impact of coverage and second-dose compliance was also explored. RESULTS: Compared with no vaccination, RZV would lead to a reduction of 30 262 HZ and 5409 PHN cases while ZVL would lead to a reduction of 7909 HZ and 3567 PHN cases. The number needed to vaccinate to prevent 1 HZ case is 12 with RZV and 45 with ZVL. The highest PHI with RZV could be achieved in individuals 60 or 65 YOA. CONCLUSION: Under the model assumptions, RZV is predicted to avert more HZ and PHN cases compared with ZVL. Results were robust under different scenario and sensitivity analyses.