-
Tropical Medicine and Infectious Disease Apr 2023Flaviviruses include virus species that are major public health threats worldwide. To determine the immunity landscape of these viruses, seroprevalence studies are often... (Review)
Review
Flaviviruses include virus species that are major public health threats worldwide. To determine the immunity landscape of these viruses, seroprevalence studies are often performed using IgG ELISA, which is a simple and rapid alternative to the virus neutralization test. In this review, we aim to describe the trends in flavivirus IgG ELISA-based serosurveys. A systematic literature review using six databases was performed to collate cohort and cross-sectional studies performed on the general population. A total of 204 studies were included in this review. The results show that most studies were performed on dengue virus (DENV), whereas Japanese Encephalitis Virus (JEV) was the least studied. For geographic distribution, serosurveys followed known disease prevalence. Temporally, the number of serosurveys increased after outbreaks and epidemics except for JEV, for which studies were performed to demonstrate the effectiveness of vaccination campaigns. Commercial kits were more commonly used than in-house assays for DENV, West Nile Virus (WNV), and Zika virus (ZIKV). Overall, most studies employed an indirect ELISA format, and the choice of antigens varied per virus. This review shows that flavivirus epidemiology is related to the regional and temporal distribution of serosurveys. It also highlights that endemicity, cross-reactivities, and kit availabilities affect assay choice in serosurveys.
PubMed: 37104349
DOI: 10.3390/tropicalmed8040224 -
Journal of Infection and Public Health Sep 2022Japanese encephalitis (JE) is a viral zoonotic disease that has been found in several countries of Asia and is responsible for high mortality and morbidity of men and... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Japanese encephalitis (JE) is a viral zoonotic disease that has been found in several countries of Asia and is responsible for high mortality and morbidity of men and animals in rural and sub-urban endemic areas due to the virus re-circulation among diverse hosts and vectors. The present study estimates the prevalence of the JE virus in the vector and animal population of the Asian continent using a systematic review and meta-analysis.
METHODS
The Cochran collaborators' Preferred Reporting Items for Systematic Reviews and Meta-Analysis [PRISMA] guidelines were used for systematic review and meta-analysis. The heterogeneity was observed in meta-regression analysis due to several factors including region, species, and different diagnostic assays used in various studies. Thus we did sensitivity and subgroup analysis.
RESULTS
The prevalence of the JE virus was calculated using a total sample size of 47,391. Subgroup analysis revealed the JE virus prevalence of 39% in the Southeast Asia region, followed by East Asia with 35% and South Asia with 15% prevalence. Hence, the overall pooled prevalence of the JE virus was 26% in the Asian continent.
CONCLUSIONS
The highest proportion of infection was found in pigs amongst all animals, reinforcing the fact that they can be used as sentinels to predict outbreaks in humans. The findings of this study will enable researchers and policymakers in better understanding the disease's spatial and temporal distribution, as well as in creating and implementing location-specific JE prevention and control measures.
Topics: Animals; Culicidae; Encephalitis Virus, Japanese; Encephalitis, Japanese; Humans; Male; Mosquito Vectors; Prevalence; Swine
PubMed: 35914358
DOI: 10.1016/j.jiph.2022.07.010 -
BMJ Global Health Oct 2023Microarray patches (MAPs) deliver vaccines to the epidermis and the upper dermis, where abundant immune cells reside. There are several potential benefits to using MAPs,... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Microarray patches (MAPs) deliver vaccines to the epidermis and the upper dermis, where abundant immune cells reside. There are several potential benefits to using MAPs, including reduced sharps risk, thermostability, no need for reconstitution, tolerability and self-administration. We aimed to explore and evaluate the immunogenicity, safety, usability and acceptability of MAPs for vaccination.
METHODS
We searched CINAHL, Cochrane Library, Ovid Embase, Ovid MEDLINE and Web of Science from inception to January 2023. Eligibility criteria included all research studies in any language, which examined microarrays or microneedles intended or used for vaccination and explored immunogenicity, safety, usability or acceptability in their findings. Two reviewers conducted title and abstract screening, full-text reviewing and data extraction.
RESULTS
Twenty-two studies were included (quantitative=15, qualitative=2 and mixed methods=5). The risk of bias was mostly low, with two studies at high risk of bias. Four clinical trials were included, three using influenza antigens and one with Japanese encephalitis delivered by MAP. A meta-analysis indicated similar or higher immunogenicity in influenza MAPs compared with needle and syringe (N&S) (standardised mean difference=10.80, 95% CI: 3.51 to 18.08, p<0.00001). There were no significant differences in immune cell function between MAPs and N&S. No serious adverse events were reported in MAPs. Erythema was more common after MAP application than N&S but was brief and well tolerated. Lower pain scores were usually reported after MAP application than N&S. Most studies found MAPs easy to use and highly acceptable among healthcare professionals, laypeople and parents.
CONCLUSION
MAPs for vaccination were safe and well tolerated and evoked similar or enhanced immunogenicity than N&S, but further research is needed. Vaccine uptake may be increased using MAPs due to less pain, enhanced thermostability, layperson and self-administration. MAPs could benefit at-risk groups and low and middle-income countries.
PROSPERO REGISTRATION NUMBER
CRD42022323026.
Topics: Humans; Influenza, Human; Vaccination; Vaccines; Pain
PubMed: 37827725
DOI: 10.1136/bmjgh-2023-012247 -
Scientific Reports Jan 2023The increasing trend of mosquito-borne pathogens demands more accurate global estimations of infection and transmission risks between mosquitoes. Here, we systematically...
The increasing trend of mosquito-borne pathogens demands more accurate global estimations of infection and transmission risks between mosquitoes. Here, we systematically review field and laboratory studies to assess the natural field infection and experimental laboratory transmission risk in Culex mosquitoes. We studied four worldwide flaviviruses: West Nile, Usutu, Japanese encephalitis, and St. Louis encephalitis, belonging to the Japanese encephalitis Serocomplex (JES). The PRISMA statement was carried out for both approaches. The Transmission-Infection Risk of the diverse mosquito species for the different viruses was estimated through seven variables. We considered 130 and 95 articles for field and experimental approach, respectively. We identified 30 species naturally infected, and 23 species capable to transmit some of the four flaviviruses. For the JES, the highest Transmission-Infection Risk estimate was recorded in Culex quinquefasciatus (North America). The maximum Infection-Transmission Risk values for West Nile was Culex restuans, for Usutu it was Culex pipiens (Europe), for St. Louis encephalitis Culex quinquefasciatus (North America), and for Japanese encephalitis Culex gelidus (Oceania). We conclude that on a worldwide scale, a combination of field and experimental data offers a better way of understanding natural infection and transmission risks between mosquito populations.
Topics: Animals; Encephalitis Viruses, Japanese; Mosquito Vectors; West Nile virus; West Nile Fever; Encephalitis, St. Louis; Encephalitis, Japanese; Flavivirus; Culicidae; Culex
PubMed: 36609450
DOI: 10.1038/s41598-022-27236-1 -
International Journal of Infectious... Jan 2021Findings were published in 2015 that highlighted the endemicity of Japanese Encephalitis (JE) in the Philippines. The policymakers responded by conducting an...
BACKGROUND
Findings were published in 2015 that highlighted the endemicity of Japanese Encephalitis (JE) in the Philippines. The policymakers responded by conducting an immunization campaign and strengthening the surveillance system. Using data on the revitalized surveillance system, the epidemiology of JE in the country was updated.
METHODS
Electronic databases were searched, and conference proceedings related to JE in the Philippines were identified until 31 December 2018. Surveillance data from 01 January 2014 to 31 December 2017 were used. The 2015 population census was used to estimate the national and regional incidence for children aged <15 years.
RESULTS
Four studies reported the seroprevalence of JE in the Philippines, which showed increasing seroprevalence with increasing age. Seroprevalence rates were from 0% for infants (aged <1 year) to 65.7% in adolescents (12-18 years) before the immunization campaign. Among five studies on the clinical profile of JE, case fatality ranged from 0 to 21.1% and neurologic sequelae ranged from 5.2 to 81.8% of diagnosed cases. In the surveillance data, JE cases peaked annually from July to October, coinciding with the wet season. The national incidence was estimated at a minimum of 0.7 JE cases/100,000 among children aged <15 years, but higher rates were seen in the northern regions of the country.
CONCLUSION
Improved surveillance affirmed the burden of JE in the Philippines. A subnational immunization campaign in April 2019 was conducted in the northern regions of the country. This paper highlights the importance of including the JE vaccine in the immunization program and sustained high-quality surveillance to monitor its impact on JE control.
Topics: Databases, Factual; Encephalitis, Japanese; Humans; Immunization Programs; Incidence; Japanese Encephalitis Vaccines; Philippines; Seroepidemiologic Studies
PubMed: 33127505
DOI: 10.1016/j.ijid.2020.10.061 -
Vaccine Mar 2023Immunization is an essential component of national health plans. However, the growing number of new vaccine introductions, vaccination campaigns and increasing... (Review)
Review
Immunization is an essential component of national health plans. However, the growing number of new vaccine introductions, vaccination campaigns and increasing administrative costs create logistic and financial challenges, especially in resource-limited settings. Sub-national geographic targeting of vaccination programs is a potential strategy for governments to reduce the impact of infectious disease outbreaks while optimizing resource allocation and reducing costs, promoting sustainability of critically important national immunization plans. We conducted a systematic review of peer-reviewed literature to identify studies that investigated the cost-effectiveness of geographically targeted sub-national vaccination programs, either through routine immunization or supplementary immunization activities. A total of 16 studies were included in our review, covering nine diseases of interest: cholera, dengue, enterotoxigenic Escherichia coli (ETEC), hepatitis A, Japanese encephalitis, measles, rotavirus, Shigella and typhoid fever. All studies modelled cost-effectiveness of geographically targeted vaccination. Despite the variation in study design, disease focus and country context, studies generally found that in countries where a heterogenous burden of disease exists, sub-national geographic targeting of vaccination programs in areas of high disease burden was more cost-effective than a non-targeted strategy. Sensitivity analysis revealed that cost-effectiveness was most sensitive to variations in vaccine price, vaccine efficacy, mortality rate, administrative and operational costs, discount rate, and treatment costs. This systematic review identified several key characteristics related to geographic targeting of vaccination, including the vaccination strategy used, variations in modelling parameters and their impact on cost-effectiveness. Additional research and guidance is needed to support the appropriateness and feasibility of geographically targeted vaccination and to determine what country context would make this a viable complement to routine immunization programs.
Topics: Cost-Benefit Analysis; Vaccination; Immunization Programs; Immunization; Vaccines
PubMed: 36781333
DOI: 10.1016/j.vaccine.2023.02.006 -
BMJ Global Health Apr 2022Arthropod-borne viruses (arboviruses) are of notable public health importance worldwide, owing to their potential to cause explosive outbreaks and induce debilitating... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Arthropod-borne viruses (arboviruses) are of notable public health importance worldwide, owing to their potential to cause explosive outbreaks and induce debilitating and potentially life-threatening disease manifestations. This systematic review and meta-analysis aims to assess the relationship between markers of socioeconomic position (SEP) and infection due to arboviruses with mosquito vectors.
METHODS
We conducted a systematic search on PubMed, Embase, and LILACS databases to identify studies published between 1980 and 2020 that measured the association of SEP markers with arbovirus infection. We included observational studies without geographic location or age restrictions. We excluded studies from grey literature, reviews and ecological studies. Study findings were extracted and summarised, and pooled estimates were obtained using random-effects meta-analyses.
RESULTS
We identified 36 observational studies using data pertaining to 106 524 study participants in 23 geographic locations that empirically examined the relationship between socioeconomic factors and infections caused by seven arboviruses (dengue, chikungunya, Japanese encephalitis, Rift Valley fever, Sindbis, West Nile and Zika viruses). While results were varied, descriptive synthesis pointed to a higher risk of arbovirus infection associated with markers of lower SEP, including lower education, income poverty, low healthcare coverage, poor housing materials, interrupted water supply, marital status (married, divorced or widowed), non-white ethnicities and migration status. Pooled crude estimates indicated an increased risk of arboviral infection associated with lower education (risk ratio, RR 1.5 95% CI 1.3 to 1.9); I=83.1%), interruption of water supply (RR 1.2; 95% CI 1.1 to 1.3; I=0.0%) and having been married (RR 1.5 95% CI 1.1 to 2.1; I=85.2%).
CONCLUSION
Evidence from this systematic review suggests that lower SEP increases the risk of acquiring arboviral infection; however, there was large heterogeneity across studies. Further studies are required to delineate the relationship between specific individual, household and community-level SEP indicators and arbovirus infection risks to help inform targeted public health interventions.
PROSPERO REGISTRATION NUMBER
CRD42019158572.
Topics: Animals; Arbovirus Infections; Arboviruses; Humans; Mosquito Vectors; Socioeconomic Factors; Zika Virus; Zika Virus Infection
PubMed: 35428678
DOI: 10.1136/bmjgh-2021-007735 -
Malaria Journal Mar 2024Anopheles vagus (subgenus Cellia) has been identified as a vector for malaria, filariasis, and Japanese encephalitis in Asia. Sporozoites of Plasmodium falciparum and... (Review)
Review
BACKGROUND
Anopheles vagus (subgenus Cellia) has been identified as a vector for malaria, filariasis, and Japanese encephalitis in Asia. Sporozoites of Plasmodium falciparum and Plasmodium vivax have been found in this zoophilic mosquito in Asia and Indonesia. This study systematically reviews publications regarding An. vagus species, variation, bio-ecology, and malaria transmission in various localities in Asia, especially Indonesia, to determine whether the current data support An. vagus as a species complex.
METHODS
The databases Pubmed, Scopus, Europe PMC, and Proquest were searched to identify information regarding the morphology, karyotypes, polytene chromosome, cross-mating, ecology, and molecular identification of An. vagus was then evaluated to determine whether there were possible species complexes.
RESULTS
Of the 1326 articles identified, 15 studies were considered for synthesis. The Anopheles spp. samples for this study came from Asia. Eleven studies used morphology to identify An. vagus, with singular studies using each of karyotype identification, chromosomal polytene identification, and cross-breeding experiments. Ten studies used molecular techniques to identify Anopheles spp., including An. vagus. Most studies discovered morphological variations of An. vagus either in the same or different areas and ecological settings. In this review, the members of An. vagus sensu lato grouped based on morphology (An. vagus, An. vagus vagus, An. vagus limosus, and An. limosus), karyotyping (form A and B), and molecular (An. vagus genotype A and B, An. vagus AN4 and AN5). Genetic analysis revealed a high conservation of the ITS2 fragment among members except for the An. vagus genotype B, which was, in fact, Anopheles sundaicus. This review also identified that An. vagus limosus and An. vagus vagus were nearly identical to the ITS2 sequence.
CONCLUSION
Literature review studies revealed that An. vagus is conspecific despite the distinct morphological characteristic of An. vagus and An. limosus. Further information using another barcoding tool, such as mitochondrial COI and ND6 and experimental cross-mating between the An. vagus and An. limosus may provide additional evidence for the status of An. vagus as a species complex.
Topics: Animals; Phylogeny; Anopheles; Genotype; Mosquito Vectors; Malaria
PubMed: 38539155
DOI: 10.1186/s12936-024-04888-0 -
PharmacoEconomics Oct 2020Cost-of-illness data from empirical studies provide insights into the use of healthcare resources including both expenditures and the opportunity cost related to... (Review)
Review
BACKGROUND
Cost-of-illness data from empirical studies provide insights into the use of healthcare resources including both expenditures and the opportunity cost related to receiving treatment.
OBJECTIVE
The objective of this systematic review was to gather cost data and relevant parameters for hepatitis B, pneumonia, meningitis, encephalitis caused by Japanese encephalitis, rubella, yellow fever, measles, influenza, and acute gastroenteritis in children in low- and middle-income countries.
DATA SOURCES
Peer-reviewed studies published in public health, medical, and economic journals indexed in PubMed (MEDLINE), Embase, and EconLit.
STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS
Studies must (1) be peer reviewed, (2) be published in 2000-2016, (3) provide cost data for one of the nine diseases in children aged under 5 years in low- and middle-income countries, and (4) generated from primary data collection.
LIMITATIONS
We cannot exclude missing a few articles in our review. Measures were taken to reduce this risk. Several articles published since 2016 are omitted from the systematic review results, these articles are included in the discussion.
CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS
The review yielded 37 articles and 267 sets of cost estimates. We found no cost-of-illness studies with cost estimates for hepatitis B, measles, rubella, or yellow fever from primary data. Most estimates were from countries in Gavi preparatory (28%) and accelerated (28%) transition, followed by those who are initiating self-financing (22%) and those not eligible for Gavi support (19%). Thirteen articles compared household expenses to manage illnesses with income and two articles with other household expenses, such as food, clothing, and rent. An episode of illness represented 1-75% of the household's monthly income or 10-83% of its monthly expenses. Articles that presented both household and government perspectives showed that most often governments incurred greater costs than households, including non-medical and indirect costs, across countries of all income statuses, with a few notable exceptions. Although limited for low- and middle-income country settings, cost estimates generated from primary data collection provided a 'real-world' estimate of the economic burden of vaccine-preventable diseases. Additional information on whether common situations preventing the application of official clinical guidelines (such as medication stock-outs) occurred would help reveal deficiencies in the health system. Improving the availability of cost-of-illness evidence can inform the public policy agenda about healthcare priorities and can help to operationalize the healthcare budget in local health systems to respond adequately to the burden of illness in the community.
Topics: Child; Cross-Sectional Studies; Developing Countries; Humans; Income; Prospective Studies; Retrospective Studies
PubMed: 32748334
DOI: 10.1007/s40273-020-00940-4 -
Viruses Oct 2019Despite the existence of human vaccines, Japanese encephalitis (JE) remains the leading cause of human encephalitis in Asia. Pigs are described as the main amplifying...
Despite the existence of human vaccines, Japanese encephalitis (JE) remains the leading cause of human encephalitis in Asia. Pigs are described as the main amplifying host, but their role in JE epidemiology needs to be reassessed in order to identify and implement efficient control strategies, for both human and animal health. We aimed to provide a systematic review of publications linked to JE in swine, in terms of both individual and population characteristics of JE virus (JEV) infection and circulation, as well as observed epidemiological patterns. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement to select and analyze relevant articles from the Scopus database, 127 of which were included in the review. Pigs are central, but the implication of secondary hosts cannot be ruled out and should be further investigated. Although human vaccination cannot eradicate the virus, it is clearly the most important means of preventing human disease. However, a better understanding of the actual involvement of domestic pigs as well as other potential JEV hosts in different JEV epidemiological cycles and patterns could help to identify additional/complementary control measures, either by targeting pigs or not, and in some specific epidemiological contexts, contribute to reduce virus circulation and protect humans from JEV infection.
Topics: Animals; Communicable Disease Control; Culex; Disease Reservoirs; Encephalitis Virus, Japanese; Encephalitis, Japanese; Humans; Japanese Encephalitis Vaccines; Swine; Swine Diseases; Vaccination
PubMed: 31618959
DOI: 10.3390/v11100949