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.

Review of the unmet medical need for vaccination in adults with immunocompromising conditions: An Indian perspective.

Immunocompromised (IC) populations are at increased risk of vaccine-preventable diseases (VPDs). In India, the concern of VPDs in IC populations is particularly acute due to the prevalence of crowded living situations, poor sanitation and variable access to healthcare services. We present a narrative review of IC-related disease and economic burden, risk of VPDs and vaccination guidelines, based on global and India-specific literature (2000-2022). IC conditions considered were cancer, diabetes mellitus, chronic kidney disease, respiratory disorders, disorders treated with immunosuppressive therapy, and human immune deficiency virus (HIV). The burden of IC populations in India is comparable to the global population, except for cancer and HIV, which have lower prevalence compared with the global average. Regional and socioeconomic inequalities exist in IC prevalence; VPDs add to the burden of IC conditions, especially in lower income strata. Adult vaccination programs could improve health and reduce the economic impact of VPDs in IC populations.

What is the context?The population is aging, both globally and in India. Older age is associated with a weakened immune system. People with an immunocompromised (IC) status have a higher risk of contracting infections. The combination of these conditions greatly increases risk from infectious disease. A large percentage of infections, referred to as vaccine-preventable diseases (VPDs), could be avoided by vaccination. However, India-specific guidelines for adult immunization are limited and there is a low awareness of these recommendations among healthcare professionals and patients. What is new? The proportion of people with IC conditions in India is comparable to that seen in other countries. However, the risk of VPDs, such as influenza and bacterial pneumonia, is of particular concern in India; several factors, such as crowded living situation, poor hygienic conditions, and lack of access to healthcare may favor the spread of infections. The consequences of infections have the greatest impact on families with low income. Furthermore, only few India-specific guidelines exist with recommendations for adult immunization. What is the impact? There is a need to protect the growing IC populations against VPDs. The introduction of public healthcare and the experience from the nationwide COVID−19 immunization program in India provide an opportunity to extend adult vaccination programs covering other VPDs. Immunization programs could reduce the economic and disease burden associated with VPDs. Clear national guidelines and communication strategies are required to increase awareness of the benefit of vaccination.

Systematic Literature Review of Herpes Zoster Disease Burden in Southeast Asia.

INTRODUCTION: Herpes zoster (HZ; i.e., shingles) is caused by the reactivation of varicella zoster virus leading to a painful dermatomal rash. An increasing trend in cases of HZ is evident worldwide; however, there is a lack of comprehensive reviews for Southeast Asian countries. METHODS: We performed a systematic literature review of articles published until May 2022 that reported HZ epidemiology, clinical management, and health economic data in six Southeast Asian countries: Indonesia, Malaysia, the Philippines, Singapore, Thailand, and Vietnam. Literature searches were conducted in Medline, Scopus, Embase, and gray literature. Articles written in English or local languages were considered for inclusion. RESULTS: In total, 72 publications were included in the study; 22 were case studies and over 60% originated in Singapore and Thailand. Only two studies (data from Thailand) reported incidence of HZ. The proportion of patients reported with HZ was 0.68-0.7% among dermatology clinics, 0.14% at one emergency department (5.3% of dermatology cases) in Singapore, and 3% of admissions at another hospital in Singapore. Pain was the most common symptom associated with HZ, reported in 74.21-100% of patients. HZ complications were reported in 10.2-21.2% of patients, and the proportions with postherpetic neuralgia and HZ ophthalmicus were 6.3-50% and 4.98-28.57%, respectively. Additionally, there is a lack of comprehensive, up-to-date HZ economic data, with only six studies identified for the Philippines, Singapore, and Thailand. CONCLUSIONS: Overall, there are limited data reporting incidence and prevalence of HZ in Southeast Asia at a national level. High rates of complications, symptoms, and abundance of case reports suggest substantial healthcare resource utilization for patients with HZ and highlight the need for further research in Southeast Asia assessing the societal impact.

Melioidosis in the Philippines.

The first documented case of melioidosis in the Philippines occurred in 1948. Since then, there have been sporadic reports in the literature about travelers diagnosed with melioidosis after returning from the Philippines. Indigenous cases, however, have been documented rarely, and under-reporting is highly likely. This review collated all Philippine cases of melioidosis published internationally and locally, as well as unpublished case series and reports from different tertiary hospitals in the Philippines. In total, 25 papers and 41 cases were identified. Among these, 23 were indigenous cases (of which 20 have not been previously reported in the literature). The most common co-morbidity present was diabetes mellitus, and the most common presentations were pulmonary and soft tissue infections. Most of the cases received ceftazidime during the intensive phase, while trimethoprim-sulfamethoxazole was given during the eradication phase. The known mortality rate was 14.6%, while 4.9% of all cases were reported to have had recurrence. The true burden of melioidosis in the country is not well defined. A lack of awareness among clinicians, a dearth of adequate laboratories, and the absence of a surveillance system for the disease are major challenges in determining the magnitude of the problem.