Clinical Efficacy, Safety, and Immunogenicity of a Live Attenuated Tetravalent Dengue Vaccine (CYD-TDV) in Children: A Systematic Review with Meta-analysis

A systematic review on malaria and dengue vaccines for the effective management of these mosquito borne diseases: Improving public health

Insect vector-borne diseases (VBDs) pose significant global health challenges, particularly in tropical and subtropical regions. The WHO has launched the "Global Vector Control Response (GVCR) 2017-2030" to address these diseases, emphasizing a comprehensive approach to vector control. This systematic review investigates the potential of malaria and dengue vaccines in controlling mosquito-borne VBDs, aiming to alleviate disease burdens and enhance public health. Following PRISMA 2020 guidelines, the review incorporated 39 new studies out of 934 identified records. It encompasses various studies assessing malaria and dengue vaccines, emphasizing the significance of vaccination as a preventive measure. The findings indicate variations in vaccine efficacy, duration of protection, and safety considerations for each disease, influencing public health strategies. The review underscores the urgent need for vaccines to combat the increasing burden of VBDs like malaria and dengue, advocating for ongoing research and investment in vaccine development.

Retrospective Genomic Characterization of a 2017 Dengue Virus Outbreak, Burkina Faso

Knowledge of contemporary genetic composition of dengue virus (DENV) in Africa is lacking. By using next-generation sequencing of samples from the 2017 DENV outbreak in Burkina Faso, we isolated 29 DENV genomes (5 serotype 1, 16 serotype 2 [DENV-2], and 8 serotype 3). Phylogenetic analysis demonstrated the endemic nature of DENV-2 in Burkina Faso. We noted discordant diagnostic results, probably related to genetic divergence between these genomes and the Trioplex PCR. Forward and reverse1 primers had a single mismatch when mapped to the DENV-2 genomes, probably explaining the insensitivity of the molecular test. Although we observed considerable homogeneity between the Dengvaxia and TetraVax-DV-TV003 vaccine strains as well as B cell epitopes compared with these genomes, we noted unique divergence. Continual surveillance of dengue virus in Africa is needed to clarify the ongoing novel evolutionary dynamics of circulating virus populations and support the development of effective diagnostic, therapeutic, and preventive countermeasures.

Evolving pharmacovigilance requirements with novel vaccines and vaccine components

This paper explores the pipeline of new and upcoming vaccines as it relates to monitoring their safety. Compared with most currently available vaccines, that are constituted of live attenuated organisms or inactive products, future vaccines will also be based on new technologies. Several products that include such technologies are either already licensed or at an advanced stage of clinical development. Those include viral vectors, genetically attenuated live organisms, nucleic acid vaccines, novel adjuvants, increased number of antigens present in a single vaccine, novel mode of vaccine administration and thermostabilisation. The Global Advisory Committee on Vaccine Safety (GACVS) monitors novel vaccines, from the time they become available for large scale use. GACVS maintains their safety profile as evidence emerges from post-licensure surveillance and observational studies. Vaccines and vaccine formulations produced with novel technologies will have different safety profiles that will require adapting pharmacovigilance approaches. For example, GACVS now considers viral vector templates developed on the model proposed by Brighton Collaboration. The characteristics of those novel products will also have implications for the risk management plans (RMPs). Questions related to the duration of active monitoring for genetic material, presence of adventitious agents more easily detected with enhanced biological screening, or physiological mechanisms of novel adjuvants are all considerations that will belong to the preparation of RMPs. In addition to assessing those novel products and advising experts, GACVS will also consider how to more broadly communicate about risk assessment, so vaccine users can also benefit from the committee’s advice.

An Overview of Current Uses and Future Opportunities for Computer-Assisted Design of Vaccines for Neglected Tropical Diseases

Neglected tropical diseases are infectious diseases that impose high morbidity and mortality rates over 1.5 billion people worldwide. Originally restricted to tropical and subtropical regions, changing climate conditions have increased their potential to emerge elsewhere. Control of their impact suffers from shortages like poor epidemiological surveillance or irregular drug distribution, and some NTDs still lack of appropriate diagnostics and/or efficient therapeutics. For these, availability of vaccines to prevent new infections, or the worsening of those already established, would mean a major breakthrough. However, only dengue and rabies count with approved vaccines at present. Herein, we review the state-of-the-art of vaccination strategies for NTDs, setting the focus on third generation vaccines and the concept of reverse vaccinology. Its capability to address pathogens´ biological complexity, likely contributing to save developmental costs is discussed. The use of computational tools is a fundamental aid to analyze increasingly large datasets aimed at designing vaccine candidates with the highest, possibly, opportunities to succeed. Ultimately, we identify and analyze those studies that took an in silico approach to find vaccine candidates, and experimentally assessed their immunogenicity and/or protection capabilities.

Phenotype and functionality of follicular helper T cells in patients with acute dengue infection

Background

The association of functionality and phenotype of follicular helper T cells (Tfh) with dengue virus (DENV) specific antibody responses and clinical disease severity has not been well studied.

Methods

We investigated the phenotype and functionality of Tfh cells and plasmablasts in adult patients (DF = 18, DHF = 22) with acute dengue (day 4 to 8 since onset of fever) of varying severity using multiparametric flowcytometry. The properties of Tfh cells were correlated with viraemia, disease severity, plasmablast responses and DENV-specific serum antibody responses. We further evaluated the kinetics of neutralizing antibodies (Neut50) throughout the course of illness in order to evaluate their association with clinical disease severity and viraemia.

Results

Tfh cells (especially those producing IL-21 and co-expressing PD-1 and ICOS) were found to be significantly expanded (p < 0.0001) and highly activated in patients with DHF compared to those with DF. The frequency of Tfh cells significantly correlated with DENV-specific IgG, NS1-specific antibodies and Neut50 antibody titres in patients with DHF but not in those with DF. Although the Neut50 titres increased during the course of acute secondary DENV infection, they showed differences based on serotype. For instance, the Neut50 titres were significantly higher during the latter part of illness in patients with DF compared to DHF in DENV1 infection, while in DENV2, patients with DHF had significantly higher titres. The viral loads during early illness did not correlate with the subsequent rise in the Neut50 antibody titres during any time point of illness.

Conclusions

The expansion of Tfh cells is associated with DHF and DENV-specific IgG, NS1-specific and neutralizing antibodies. Neut50 titres did not associate with disease severity or viraemia at the point of first presentation during the febrile phase, but later titres do show differential association with severity in patients with DENV1 compared to DENV2.

Advancements in developing an effective and preventive dengue vaccine

Every year millions of people in various tropical and subtropical regions encounter infection with dengue virus. Within the last few decades, its prevalence has increased up to 30-fold globally and presently these viruses have been transmitted in more than 100 countries. Scientists contributed to the development of tetravalent dengue vaccine by adopting numerous approaches including live vaccine, recombinant protein vaccine, DNA vaccine and virus-vectored vaccines. A vaccine should be genetically stable, equally effective against all serotypes, must be in-expensive and commercially available. Chimeric yellow fever virus-tetravalent dengue vaccine (CYD-TDV) is the first licensed vaccine developed by Sanofi Pasteur in December 2015, but this vaccine is not fully effective against different dengue virus serotypes (Sanofi Pasteur, Lyon, France). This review explores the advancements and challenges involved in the development of dengue vaccine.

Molecular characteristics and replication mechanism of dengue, zika and chikungunya arboviruses, and their treatments with natural extracts from plants: An updated review

Viruses transmitted by arthropods (arboviruses) are the etiological agents of several human diseases with worldwide distribution; including dengue (DENV), zika (ZIKV), yellow fever (YFV), and chikungunya (CHIKV) viruses. These viruses are especially important in tropical and subtropical regions; where, ZIKV and CHIKV are involved in epidemics worldwide, while the DENV remains as the biggest problem in public health. Factors, such as, environmental conditions promote the distribution of vectors, deficiencies in health services, and lack of effective vaccines, guarantee the presence of these vector-borne diseases. Treatment against these viral diseases is only palliative since available therapies formulated lack to demonstrate specific antiviral activity and vaccine candidates fail to demonstrate enough effectiveness. The use of natural products, as therapeutic tools, is an ancestral practice in different cultures. According to WHO 80 % of the population of some countries from Africa and Asia depend on the use of traditional medicines to deal with some diseases. Molecular characteristics of these viruses are important in determining its cellular pathogenesis, emergence, and dispersion mechanisms, as well as for the development of new antivirals and vaccines to control strategies. In this review, we summarize the current knowledge of the molecular structure and replication mechanisms of selected arboviruses, as well as their mechanism of entry into host cells, and a brief overview about the potential targets accessed to inhibit these viruses in vitro and a summary about their treatment with natural extracts from plants.

The Interplay between Dengue Virus and the Human Innate Immune System: A Game of Hide and Seek

With 40% of the world population at risk, infections with dengue virus (DENV) constitute a serious threat to public health. While there is no antiviral therapy available against this potentially lethal disease, the efficacy of the only approved vaccine is not optimal and its safety has been recently questioned. In order to develop better vaccines based on attenuated and/or chimeric viruses, one must consider how the human immune system is engaged during DENV infection. The activation of the innate immunity through the detection of viruses by cellular sensors is the first line of defence against those pathogens. This triggers a cascade of events which establishes an antiviral state at the cell level and leads to a global immunological response. However, DENV has evolved to interfere with the innate immune signalling at multiple levels, hence dampening antiviral responses and favouring viral replication and dissemination. This review elaborates on the interplay between DENV and the innate immune system. A special focus is given on the viral countermeasure mechanisms reported over the last decade which should be taken into consideration during vaccine development.

Amplificación de la infección dependiente de anticuerpos en la inmunopatogénesis del dengue grave, implicaciones para el desarrollo y uso de las vacunas

Actualmente, la infección por el virus de dengue (DENV) es uno de los problemas más importantes de salud pública en países tropicales y endémicos como Colombia, pues en tanto puede ser producida por cuatro diferentes serotipos virales, durante las infecciones secundarias se presentan frecuentemente cuadros más severos que incluso pueden llevar a desenlaces fatales. El centro de la fisiopatología del dengue grave es el daño producido al endotelio, que se traduce en un aumento en la permeabilidad vascular que se evidencia como fuga plasmática, descontrol en la coagulación y daño de órganos. Aunque hay varias teorías que explican la enfermedad severa, el fenómeno denominado amplificación de la infección dependiente de anticuerpos (antibody dependent enhancement, ADE) es el más conocido. En este, se postula que el virus causante de una infección secundaria es reconocido, pero no neutralizado, por anticuerpos generados en la infección previa e internalizado en las células susceptibles usando receptores Fc-gamma, lo cual aumenta la replicación viral e induce modificaciones en la respuesta inmune celular que contribuyen al desarrollo de dengue grave. En este escrito, se realiza una revisión de los hallazgos sobre los mecanismos involucrados en el fenómeno de ADE y cómo pueden contribuir a la progresión hacia dengue grave, describiendo los conceptos de ADE extrínseco e intrínseco, además de como este fenómeno debe ser tenido en cuenta para el diseño, desarrollo e implementación de una vacuna para dengue, en tanto es capaz de afectar su eficacia y seguridad.

Efficacy, immunogenicity and safety of a recombinant tetravalent dengue vaccine (CYD-TDV) in children aged 2-17 years: systematic review and meta-analysis

BACKGROUND

Randomised controlled trials have evaluated the recombinant tetravalent dengue vaccine (CYD-TDV). However, individual results may have little power to identify differences among the populations studied.

OBJECTIVE

To evaluate efficacy, immunogenicity and safety of CYD-TDV in the prevention of dengue in children aged 2-17 years.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

MEDLINE (from 1950 to 5 December 2018), EMBASE (from 1947 to 5 December 2018) and Cochrane (from 1993 to 5 December 2018).

ELIGIBILITY CRITERIA OF STUDIES

Randomised trials comparing efficacy, immunogenicity and safety of CYD-TDV with placebo or other vaccines for preventing dengue cases in children aged 2-17 years.

OUTCOME MEASURES

Efficacy, immunogenicity and safety of CYD-TDV.

STUDY APPRAISAL AND METHODS

Calculations were made of relative risk (RR) and mean difference (MD) for dichotomous and continuous outcomes, respectively. All estimates were calculated considering a 95% CI estimate. A p<0.05 was considered statistically significant.

RESULTS

Nine studies involving 34 248 participants were included. The overall efficacy of CYD-TDV was 60% (RR 0.40 (0.30 to 0.54)). Serotype-specific efficacy of the vaccine was 51% for dengue virus type-1 (DENV-1) (RR 0.49 (0.39 to 0.63)); 34% for DENV-2 (RR 0.66 (0.50 to 0.86)); 75% for DENV-3 (RR 0.25 (0.18 to 0.35)) and 77% for DENV-4 (RR 0.23 (0.15 to 0.34)). Overall immunogenicity (MD) of CYD-TDV was 225.13 (190.34 to 259.93). Serotype-specific immunogenicity was: DENV-1: 176.59 (123.36 to 229.83); DENV-2: 294.21 (181.98 to 406.45); DENV-3: 258.78 (146.72 to 370.84) and DENV-4: 189.35 (141.11 to 237.59). The most common adverse events were headache and pain at the injection site.

LIMITATIONS

The main limitation of this study was unclear or incomplete data.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

CYD-TDV is considered safe and able to partially protect children and adolescents against four serotypes of DENV for a 1-year period. Despite this, research should prioritise improvements in vaccine efficacy, thus proving higher long-term protection against all virus serotypes.

PROSPERO REGISTRATION NUMBER

CRD42016043628.

Analysis of dengue specific memory B cells, neutralizing antibodies and binding antibodies in healthy adults from India

BACKGROUND

The Indian population is facing highest dengue burden worldwide supporting an urgent need for vaccines. For vaccine introduction, evaluation and interpretation it is important to gain a critical understanding of immune memory induced by natural exposure. However, immune memory to dengue remains poorly characterized in this region.

METHODS

We enumerated levels of dengue specific memory B cells (MBC), neutralizing (NT) and binding antibodies in healthy adults (n=70) from New Delhi.

RESULTS

NT-antibodies, binding antibodies and MBC were detectable in 86%, 86.56% and 81.63% of the subjects respectively. Among the neutralizing positive subjects, 58%, 27%, 5% and 10% neutralized all four, any three, any two and any one dengue serotypes respectively. The presence of the neutralizing antibodies was associated with the presence of the MBC and binding antibodies. However, a massive interindividual variation was observed in the levels of the neutralizing antibodies (range, <1:50-1:30,264), binding antibodies (range, 1:3,000-1:134,000,) as well as the MBC (range=0.006%-5.05%).

CONCLUSION

These results indicate that a vast majority of the adults are immune to multiple dengue serotypes and show massive interindividual variation in neutralizing/binding antibodies and MBCs - emphasizing the importance of monitoring multiple parameters of immune memory in order to properly plan, evaluate and interpret dengue vaccines.

Customers' preferences and willingness to pay for a future dengue vaccination: a study of the empirical evidence in Vietnam

BACKGROUND

Dengue was endemic to Vietnam. Due to the lack of a readily available remedy, dengue vaccines (DV) have been used elsewhere to cure the disease. However, introducing DV in Vietnam has met resistance from society and the government, influencing decisions about willingness-to-pay (WTP) and other pharmacoeconomic studies. This research aimed to evaluate the extent to which Vietnamese customers would be willing to pay to vaccinate themselves and their children, if any at all, against dengue.

MATERIALS AND METHODS

This was a cross-sectional interview-based research. Contingent valuation method, combined with the bidding technique and several open-ended questions, were used to obtain the maximum WTP values for six hypothetical scenarios of two types of DV (60% efficacy for 10 years, "Type 1" vs 90% efficacy for 20 years, "Type 2").

RESULTS

The median WTP per adult for Type 1 and Type 2 DV were US$130.34 and US$217.39, respectively. The median WTP rates per parent for their own vaccination were US$86.96 (Type 1) and US$156.52 (Type 2), for their children vaccination costs were US$108.70 (Type 1) and US$195.65 (Type 2). Five factors affected the WTP rates: monthly income, marital status, area, locality and level of education.

CONCLUSION

The WTP rates for DV were high, supporting the introduction of DV in Vietnam.

Immunogenicity of different dosing schedules of the human live attenuate rotavirus vaccine (RV1) in infants and children: a meta-analysis

Rotavirus immunization strategies have become part of a comprehensive global public health program to control rotavirus-associated gastroenteritis, particularly in infants and children in developing countries. Several studies have reported the efficacy of different rotavirus vaccine dosing schedules, but with mixed findings. Therefore a systematic review of the published literature on rotavirus vaccination dosing schedules using the live attenuated RV1 rotavirus vaccine in infants and children, including randomized controlled clinical trials (RCTs), published between January 1998 to January 2018 was conducted, with meta-analysis of the published data. The literature search was performed using six databases. The initial review identified 495 publications, of which three satisfied the selection eligibility criteria. The three studies that assessed RV1 rotavirus vaccine immunogenicity compared a two-dose vaccination schedule with a three-dose vaccination schedule. The use of a three-dose vaccination schedule did not show a statistically significant seroconversion rate when compared with a two-dose vaccination schedule (OR = 0.87; 95% CI,: 0.65--1.17;, p- = 0.298). Analysis of included studies with one-month follow-up time showed that the three-dose vaccination schedule did not result in have significantly increased geometric mean concentrations (GMCs) compared with the two-dose vaccination schedule (p = 0.311).Rotavirus immunogenicity did not increase significantly with the three-dose schedule at 6, 10 and 14 weeks with the two-dose schedule at 10 and 14 weeks. These findings indicate that further controlled studies should be undertaken to support the optimum immunization schedules for rotavirus in terms of clinical effectiveness and cost-effectiveness, particularly for infants and children in developing countries.

Evaluation of cell-surface displayed synthetic consensus dengue EDIII cells as a potent oral vaccine candidate

BACKGROUND

Dengue is a rapidly spreading mosquito borne tropical viral disease affecting hundreds of millions of people across the globe annually. The dengue virus (DENV) includes four genetically distinct serotypes that cause serious life-threatening infections, including dengue hemorrhagic fever/dengue shock syndrome. Dengue vaccine development is complicated by the possibility of vaccine-enhanced severe dengue disease due to antibody-dependent enhancement by pre-existing cross-reactivity, as well as homotypic antibodies. Thus, the development of an efficacious dengue vaccine conferring simultaneous and durable immunity to each of the four DENV serotypes has not yet been developed despite years of research. For mass immunization in deeply affected resource-limited countries, oral vaccination is considered more beneficial than conventional approaches. Therefore, in a continuing effort towards designing economical and potent vaccine candidates, the current study applied yeast surface display technology to develop an oral dengue vaccine candidate using whole recombinant yeast cells displaying the recombinant fusion protein of M cell targeting ligand Co1 fused to the synthetic consensus dengue envelope domain III (scEDIII). Female Balb/c mice were orally fed with recombinant yeast cells and immunogenicity in terms of systemic and mucosal immune responses was monitored.

RESULTS

Immunofluorescence microscopy with dengue specific antibody and fluorescein isothiocyanate-conjugated anti-mouse IgG antibody clearly showed that recombinant protein Co1-scEDIII-AGA was localized on the cell surface of the respective clones in comparison with scEDIII-Co1 and Mock cells with no fluorescence. Oral dosage applications of surface displayed Co1-scEDIII-AGA stimulated a systemic humoral immune response in the form of dengue-specific serum IgG, as well as a mucosal immune response in the form of secretory immunoglobulin A (sIgA). Antigen-specific B cell responses in isolated lymphoid cells from the spleen and Peyer's patches further supported an elevated mucosal immune response. In addition, surface displayed Co1-scEDIII-AGA feeding elicited strong immune responses in comparison with scEDIII-Co1 and Mock following intraperitoneal booster with purified scEDIII antigen.

CONCLUSIONS

Surface displayed preparations of Co1-scEDIII-AGA induced strong immunogenicity compared with non-displayed scEDIII-Co1. Prior studies have supported the neutralization potential of scEDIII constructs against all four serotypes. Thus, the oral administration of genetically engineered yeast whole cells displaying biologically active Co1-scEDIII fusion protein without any further processing shows prospective as a potent oral vaccine candidate against dengue viral infection.

Neighbourhood level real-time forecasting of dengue cases in tropical urban Singapore

BACKGROUND

Dengue, a vector-borne infectious disease caused by the dengue virus, has spread through tropical and subtropical regions of the world. All four serotypes of dengue viruses are endemic in the equatorial city state of Singapore, and frequent localised outbreaks occur, sometimes leading to national epidemics. Vector control remains the primary and most effective measure for dengue control and prevention. The objective of this study is to develop a novel framework for producing a spatio-temporal dengue forecast at a neighbourhood level spatial resolution that can be routinely used by Singapore's government agencies for planning of vector control for best efficiency.

METHODS

The forecasting algorithm uses a mixture of purely spatial, purely temporal and spatio-temporal data to derive dynamic risk maps for dengue transmission. LASSO-based regression was used for the prediction models and separate sub-models were constructed for each forecast window. Data were divided into training and testing sets for out-of-sample validation. Neighbourhoods were categorised as high or low risk based on the forecast number of cases within the cell. The predictive accuracy of the categorisation was measured.

RESULTS

Close concordance between the projections and the eventual incidence of dengue were observed. The average Matthew's correlation coefficient for a classification of the upper risk decile (operational capacity) is similar to the predictive performance at the optimal 30% cut-off. The quality of the spatial predictive algorithm as a classifier shows areas under the curve at all forecast windows being above 0.75 and above 0.80 within the next month.

CONCLUSIONS

Spatially resolved forecasts of geographically structured diseases like dengue can be obtained at a neighbourhood level in highly urban environments at a precision that is suitable for guiding control efforts. The same method can be adapted to other urban and even rural areas, with appropriate adjustment to the grid size and shape.

Development of an anti-dengue NS1 IgG ELISA to evaluate exposure to dengue virus

Dengue virus infection elicits immune responses to multiple viral antigens including antibodies to dengue non-structural protein 1 (NS1) which are rapidly induced and detected within days of infection. The recombinant, live, attenuated, tetravalent dengue vaccine (CYD-TDV; Sanofi Pasteur) uses the yellow fever vaccine virus as a back-bone but expresses dengue virus pre-membrane and envelop proteins. Since CYD-TDV does not express dengue NS1, we evaluated the utility of dengue NS1-specific IgG antibodies as biomarkers of dengue exposure in CYD-TDV recipients and controls. We optimized and evaluated a quantitative anti-dengue NS1 IgG enzyme-linked immunosorbent assay (ELISA). Parameters assessed included: accuracy, dilutability/linearity, precision, limit of quantitation and specificity. The assay specificity was further evaluated using Japanese Encephalitis virus, West Nile virus, Yellow Fever virus or Zika virus positive sera samples collected following confirmed infection or vaccination. Receiver-operating-characteristics (ROC) curves as well as sensitivity and specificity for discriminating previous dengue exposure were assessed using 1250 reference samples. Overall, the anti-dengue NS1 IgG ELISA was able to discriminate previous dengue exposure from non-exposure before vaccination with CYD-TDV (ROC area under the curve > 0.9). Assessment of paired samples from 2511 vaccinated participants showed high overall agreement (93%) between pre-vaccination and post-vaccination dengue serostatus classification based on the anti-dengue NS1 IgG ELISA. However, misclassification of dengue serostatus was observed after vaccination likely due to a combination of asymptomatic dengue infections, assay variability and a modest effect of CYD-TDV on the anti-dengue NS1 IgG ELISA readout.

Experimental in vitro and in vivo systems for studying the innate immune response during dengue virus infections

Dengue is the most prevalent arboviral disease in humans and leads to significant morbidity and socioeconomic burden in tropical and subtropical areas. Dengue is caused by infection with any of the four closely related serotypes of dengue virus (DENV1-4) and usually manifests as a mild febrile illness, but may develop into fatal dengue hemorrhagic fever and shock syndrome. There are no specific antiviral therapies against dengue because understanding of DENV biology is limited. A tetravalent chimeric dengue vaccine, Dengvaxia, has finally been licensed for use, but its efficacy was significantly lower against DENV-2 infections and in dengue-naïve individuals. The identification of mechanisms underlying the interactions between DENV and immune responses will help to determine efficient therapeutic and preventive options. It has been well established how the innate immune system responds to DENV infection and how DENV overcomes innate antiviral defenses, however further progress in this field remains hampered by the absence of appropriate experimental dengue models. Herein, we review the available in vitro and in vivo approaches to study the innate immune responses to DENV.

Dengue Hemorrhagic Fever Virus in Saudi Arabia: A Review

Dengue fever is a global disease with a spectrum of clinical manifestation ranging from mild febrile disease to a severe disease in the form of dengue hemorrhagic fever and dengue shock syndrome. Dengue virus is one viral hemorrhagic fever that exists in the Kingdom of Saudi Arabia in addition to Alkhurma (Alkhurma) Hemorrhagic Fever, Chikungunya virus, Crimean-Congo Hemorrhagic Fever, and Rift Valley Fever. The disease is limited to the Western and South-western regions of Saudi Arabia, where Aedes aegypti exists. The majority of the cases in Saudi Arabia had mild disease and is related to serotypes 1-3 but not 4. The prospect for Dengue virus control relies on vector control, health education, and possibly vaccine use. Despite extensive collaborative efforts between multiple governmental sectors, including Ministry of Health, Ministry of Municipalities and Rural Affairs, and Ministry of Water, dengue remains a major public health concern in the regions affected.

Public health aspects of Dengue virus infection relevant to Australia

Dengue is endemic in over 100 countries. The disease is not endemic in Australia currently, although the mosquito vector and imported cases cause sporadic outbreaks, predominantly in Queensland. The illness dengue fever causes a spectrum of disease from asymptomatic or a minor febrile illness through to a fatal disease caused by shock from plasma leakage or haemorrhage. There is currently no specific treatment for dengue. Dengue is mainly diagnosed using serology, antigen detection and PCR. Serological diagnosis of dengue can be difficult because of cross reactions with other flaviviruses. A vaccine is available and registered in Australia, however the overall efficacy is just over 50%. Surveillance, disease recognition, outbreak control and prevention of exposure are strategies used to combat dengue in Australia.