Volume 13 · Issue 02 · 2024

Immunization is a cornerstone of public health. Despite great success, China’s National Immunization Program (NIP) faces challenges, such as the integration of several World Health Organization-recommended vaccines and other systemic issues. The Innovation Laboratory for Vaccine Delivery Research (VaxLab), supported by the Bill & Melinda Gates Foundation and established in 2021 at Duke Kunshan University, focuses on enhancing China’s NIP through research and policy advocacy. This editorial aims to summarize the key findings of the manuscripts published in the collection contributed by VaxLab team and set the future research agenda.

The collection contains eleven manuscripts discussing China’s immunization landscape and strategies to improve coverage, particularly for non-NIP vaccines like human papillomavirus vaccine (HPV), pneumococcal conjugate vaccine (PCV), Haemophilus influenzae type b vaccine (Hib), and rotavirus vaccines. Key findings include: (i) The COVID-19 vaccination campaign demonstrated China’s capacity for rapid, large-scale immunization efforts, suggesting potential for broader vaccine coverage improvements; (ii) Efforts in combating cervical cancer through the HPV vaccine indicate progress but also highlight challenges like vaccine supply and equitable access; (iii) The lag in adopting higher-valent paediatric combination vaccines in China needs attention to address regulatory and health system hurdles; (iv) Disparities in access to non-NIP vaccines underscore the need for government initiatives to improve vaccine coverage, especially for remote areas and marginalized populations; (v) Original studies emphasize the influence of caregivers’ knowledge, health workers’ financial incentives, and concerns about vaccine efficacy on immunization rates; (vi) Case studies from the Weifang City of China and Indonesia to introduce PCV offer insights on successful vaccine introduction strategies and the impact of innovative financing and government support.

The articles emphasize the need for government leadership, strategic policymaking, and public awareness to enhance vaccine coverage and equity. The VaxLab will continue strengthening China’s NIP by focusing on vaccine financing, emphasizing diversity, equity, and inclusion, and improving maternal vaccination coverage. Research will extend to Southeast Asian and Western Pacific regions, especially in middle-income countries facing challenges in vaccine financing and delivery. The collective efforts outlined in this collection show a commitment to evolving and adapting immunization strategies to meet global health goals and to provide equitable access to vaccines for all.

In Viet Nam, tuberculosis (TB) represents a devastating life-event with an exorbitant price tag, partly due to lost income from daily directly observed therapy in public sector care. Thus, persons with TB may seek care in the private sector for its flexibility, convenience, and privacy. Our study aimed to measure income changes, costs and catastrophic cost incurrence among TB-affected households in the public and private sector.

Between October 2020 and March 2022, we conducted 110 longitudinal patient cost interviews, among 50 patients privately treated for TB and 60 TB patients treated by the National TB Program (NTP) in Ha Noi, Hai Phong and Ho Chi Minh City, Viet Nam. Using a local adaptation of the WHO TB patient cost survey tool, participants were interviewed during the intensive phase, continuation phase and post-treatment. We compared income levels, direct and indirect treatment costs, catastrophic costs using Wilcoxon rank-sum and chi-squared tests and associated risk factors between the two cohorts using multivariate regression.

The pre-treatment median monthly household income was significantly higher in the private sector versus NTP cohort (USD 868 vs USD 578; P=0.010). However, private sector treatment was also significantly costlier (USD 2075 vs USD 1313; P=0.005), driven by direct medical costs which were 4.6 times higher than costs reported by NTP participants (USD 754 vs USD 164; P<0.001). This resulted in no significant difference in catastrophic costs between the two cohorts (Private: 55% vs NTP: 52%; P=0.675). Factors associated with catastrophic cost included being a single-person household [adjusted odds ratio [(aOR=13.71; 95% confidence interval (CI): 1.36–138.14; P=0.026], unemployment during treatment (aOR=10.86; 95% CI: 2.64–44.60; P<0.001) and experiencing TB-related stigma (aOR=37.90; 95% CI: 1.72–831.73; P=0.021).

Persons with TB in Viet Nam face similarly high risk of catastrophic costs whether treated in the public or private sector. Patient costs could be reduced through expanded insurance reimbursement to minimize direct medical costs in the private sector, use of remote monitoring and multi-week/month dosing strategies to avert economic costs in the public sector and greater access to social protection mechanism in general.

Schistosomiasis is highly endemic in sub-Saharan Africa and frequently imported to Europe. Male urogenital manifestations are often neglected. We aimed to ascertain the prevalence of genitourinary clinical signs and symptoms among long-term African migrants in a non-endemic European country using a serology test.

We carried out a prospective, community-based cross-sectional study of adult male migrants from sub-Saharan Africa living in Spain. Schistosoma serology tests and microscopic urine examinations were carried out, and clinical data were obtained from an electronic medical record search and a structured questionnaire.

We included 388 adult males, mean age 43.5 years [Standard Deviation (SD) = 12.0, range: 18–76]. The median time since migration to the European Union was 17 [Interquartile range (IQR): 11–21] years. The most frequent country of origin was Senegal (N = 179, 46.1%). Of the 338, 147 (37.6%) tested positive for Schistosoma. Parasite eggs were present in the urine of only 1.3%. Nine genitourinary clinical items were significantly associated with positive Schistosoma serology results: pelvic pain (45.2%; OR = 1.57, 95% CI: 1.0–2.4), pain on ejaculation (14.5%; OR = 1.85, 95% CI: 1.0–3.5), dyspareunia (12.4%; OR = 2.45, 95% CI: 1.2–5.2), erectile dysfunction (9.5%; OR = 3.10, 95% CI: 1.3–7.6), self-reported episodes of infertility (32.1%; OR = 1.69, 95% CI: 1.0–2.8), haematuria (55.2%; OR = 2.37, 95% CI: 1.5–3.6), dysuria (52.1%; OR = 2.01, 95% CI: 1.3–3.1), undiagnosed syndromic STIs (5.4%), and orchitis (20.7%; OR = 1.81, 95% CI: 1.0–3.1). Clinical signs tended to cluster.

Urogenital clinical signs and symptoms are prevalent among male African long-term migrants with a positive Schistosoma serology results. Genital involvement can be frequent even among those with long periods of non-residence in their sub-Saharan African countries of origin. Further research is needed to develop diagnostic tools and validate therapeutic approaches to chronic schistosomiasis.

Clonorchiasis and opisthorchiasis, caused by the liver flukes Clonorchis sinensis and Opisthorchis viverrini respectively, represent significant neglected tropical diseases (NTDs) in Asia. The co-existence of these pathogens in overlapping regions complicates effective disease control strategies. This study aimed to clarify the distribution and interaction of these diseases within Southeast Asia.

We systematically collated occurrence records of human clonorchiasis (n = 1809) and opisthorchiasis (n = 731) across the Southeast Asia countries. Utilizing species distribution models incorporating environmental and climatic data, coupled machine learning algorithms with boosted regression trees, we predicted and distinguished endemic areas for each fluke species. Machine learning techniques, including geospatial analysis, were employed to delineate the boundaries between these flukes.

Our analysis revealed that the endemic range of C. sinensis and O. viverrini in Southeast Asia primarily spans across part of China, Vietnam, Thailand, Laos, and Cambodia. During the period from 2000 to 2018, we identified C. sinensis infections in 84 distinct locations, predominantly in southern China (Guangxi Zhuang Autonomous Region) and northern Vietnam. In a stark contrast, O. viverrini was more widely distributed, with infections documented in 721 locations across Thailand, Laos, Cambodia, and Vietnam. Critical environmental determinants were quantitatively analyzed, revealing annual mean temperatures ranging between 14 and 20 °C in clonorchiasis-endemic areas and 24–30 °C in opisthorchiasis regions (P < 0.05). The machine learning model effectively mapped a distinct demarcation zone, demonstrating a clear separation between the endemic areas of these two liver flukes with AUC from 0.9 to1. The study in Vietnam delineates the coexistence and geographical boundaries of C. sinensis and O. viverrini, revealing distinct endemic zones and a transitional area where both liver fluke species overlap.

Our findings highlight the critical role of specific climatic and environmental factors in influencing the geographical distribution of C. sinensis and O. viverrini. This spatial delineation offers valuable insights for integrated surveillance and control strategies, particularly in regions with sympatric transmission. The results underscore the need for tailored interventions, considering regional epidemiological variations. Future collaborations integrating eco-epidemiology, molecular epidemiology, and parasitology are essential to further elucidate the complex interplay of liver fluke distributions in Asia.

Tuberculosis (TB) remains a major public health problem in Nepal, high in settings marked by prevalent gender and social inequities. Various social stratifiers intersect, either privileging or oppressing individuals based on their characteristics and contexts, thereby increasing risks, vulnerabilities and marganilisation associated with TB. This study aimed to assess the inclusiveness of gender and other social stratifiers in key health related national policies and the Health Management Information System (HMIS) of National Tuberculosis Programme (NTP) by conducting an intersectional analysis of TB cases recorded via HMIS.

A desk review of key policies and the NTP’s HMIS was conducted. Retrospective intersectional analysis utilized two secondary data sources: annual NTP report (2017–2021) and records of 628 TB cases via HMIS 6.5 from two TB centres (2017/18–2018/19). Chi-square test and multi-variate analysis was used to assess the association between social stratifers and types of TB, registration category and treatment outcome.

Gender, social inclusion and concept of intersectionality are incorporated into various health policies and strategies but lack effective implementation. NTP has initiated the collection of age, sex, ethnicity and location data since 2014/15 through the HMIS. However, only age and sex disaggregated data are routinely reported, leaving recorded social stratifiers of TB patients static without analysis and dissemination. Furthermore, findings from the intersectional analysis using TB secondary data, showed that male more than 25 years exhibited higher odds [adjusted odds ratio (aOR) = 4.95, 95% confidence interval (CI): 1.60–19.06, P = 0.01)] of successful outcome compared to male TB patients less than 25 years. Similarly, sex was significantly associated with types of TB (P < 0.05) whereas both age (P < 0.05) and sex (P < 0.05) were significantly associated with patient registration category (old/new cases).

The results highlight inadequacy in the availability of social stratifiers in the routine HMIS. This limitation hampers the NTP’s ability to conduct intersectional analyses, crucial for unveiling the roles of other social determinants of TB. Such limitation underscores the need for more disaggregated data in routine NTP to better inform policies and plans contributing to the development of a more responsive and equitable TB programme and effectively addressing disparities.

Culex pipiens pallens and Culex pipiens quinquefasciatus are the dominant species of Culex mosquitoes in China and important disease vectors. Long-term use of insecticides can cause mutations in the voltage-gated sodium channel (vgsc) gene of mosquitoes, but little is known about the current status and evolutionary origins of vgsc gene in different geographic populations. Therefore, this study aimed to determine the current status of vgsc genes in Cx. p. pallens and Cx. p. quinquefasciatus in China and to investigate the evolutionary inheritance of neighboring downstream introns of the vgsc gene to determine the impact of insecticides on long-term evolution.

Sampling was conducted from July to September 2021 in representative habitats of 22 provincial-level administrative divisions in China. Genomic DNA was extracted from 1308 mosquitoes, the IIS6 fragment of the vgsc gene on the nerve cell membrane was amplified using polymerase chain reaction, and the sequence was used to evaluate allele frequency and knockdown resistance (kdr) frequency. MEGA 11 was used to construct neighborjoining (NJ) tree. PopART was used to build a TCS network.

There were 6 alleles and 6 genotypes at the L1014 locus, which included the wild-type alleles TTA/L and CTA/L and the mutant alleles TTT/F, TTC/F, TCT/S and TCA/S. The geographic populations with a kdr frequency less than 20.00% were mainly concentrated in the regions north of 38° N, and the geographic populations with a kdr frequency greater than 80.00% were concentrated in the regions south of 30° N. kdr frequency increased with decreasing latitude. And within the same latitude, the frequency of kdr in large cities is relatively high. Mutations were correlated with the number of introns. The mutant allele TCA/S has only one intron, the mutant allele TTT/F has three introns, and the wild-type allele TTA/L has 17 introns.

Cx. p. pallens and Cx. p. quinquefasciatus have developed resistance to insecticides in most regions of China. The neighboring downstream introns of the vgsc gene gradually decreased to one intron with the mutation of the vgsc gene. Mutations may originate from multiple mutation events rather than from a single origin, and populations lacking mutations may be genetically isolated.

与双边模式相比，三方伙伴关系被视为促进更强大和更信任的伙伴关系的机会[1].然而，中国历来被认为主要依赖双边参与全球卫生[2].中坦疟疾防治合作项目由中国疾病预防控制中心国家寄生虫病研究所、中国热带病研究中心、坦桑尼亚伊法卡拉卫生研究所及资助机构于2015年至2022年开展，旨在探索中国疟疾防治经验在坦桑尼亚当地减轻疟疾疾病负担的适用性。在由前英国国际发展部（DFID）和后来的比尔及梅琳达·盖茨基金会（BMGF）资助的三方项目中，中国的合作伙伴预计将分享70多年来在控制和消除疟疾方面取得的广泛平行的做法，英国的合作伙伴将提供资源和设计全球卫生战略，而坦桑尼亚的当地工作人员将与三方合作伙伴合作，以确保项目的实施[3].在项目中，三方合作有透明的管理机制，确保项目的具体管理和实施[4]（附加文件1：图S1）。本简报旨在通过从该项目创新的三方伙伴关系中提炼经验，为中国参与全球卫生事业提供建议。

Since the COVID-19 pandemic began, a plethora of modeling studies relatedto COVID-19 have been released. While some models stand out due to their innovative approaches, others are flawed in their methodology. To assist novices, frontline healthcare workers, and public health policymakers in navigating the complex landscape of these models, we introduced a structured framework named MODELS. This framework is designed to detail the essential steps and considerations for creating a dependable epidemic model, offering direction to researchers engaged in epidemic modeling endeavors.

Despite the increasing focus on strengthening One Health capacity building on global level, challenges remain in devising and implementing real-world interventions particularly in the Asia-Pacific region. Recognizing these gaps, the One Health Action Commission (OHAC) was established as an academic community for One Health action with an emphasis on research agenda setting to identify actions for highest impact.

This viewpoint describes the agenda of, and motivation for, the recently formed OHAC. Recognizing the urgent need for evidence to support the formulation of necessary action plans, OHAC advocates the adoption of both bottom-up and top-down approaches to identify the current gaps in combating zoonoses, antimicrobial resistance, addressing food safety, and to enhance capacity building for context-sensitive One Health implementation.

By promoting broader engagement and connection of multidisciplinary stakeholders, OHAC envisions a collaborative global platform for the generation of innovative One Health knowledge, distilled practical experience and actionable policy advice, guided by strong ethical principles of One Health.

We look at the link between climate change and vector-borne diseases in low- and middle-income countries in Africa. The large endemicity and escalating threat of diseases such as malaria and arboviral diseases, intensified by climate change, disproportionately affects vulnerable communities globally. We highlight the urgency of prioritizing research and development, advocating for robust scientific inquiry to promote adaptation strategies, and the vital role that the next generation of African research leaders will play in addressing these challenges. Despite significant challenges such as funding shortages within countries, various pan-African-oriented funding bodies such as the African Academy of Sciences, the Africa Research Excellence Fund, the Wellcome Trust, the U.S. National Institutes of Health, and the Bill and Melinda Gates Foundation as well as initiatives such as the African Research Initiative for Scientific Excellence and the Pan-African Mosquito Control Association, have empowered (or are empowering) these researchers by supporting capacity building activities, including continental and global networking, skill development, mentoring, and African-led research. This article underscores the urgency of increased national investment in research, proposing the establishment of research government agencies to drive evidence-based interventions. Collaboration between governments and scientific communities, sustained by pan-African funding bodies, is crucial. Through these efforts, African nations are likely to enhance the resilience and adaptive capacity of their systems and communities by navigating these challenges effectively, fostering scientific excellence and implementing transformative solutions against climate-sensitive vector-borne diseases.