SARS-CoV-2 Vaccine Safety and Autoimmune Response.

Coronavirus disease 2019 (COVID-19) is a global public health crisis [...].

Lambda-free light chain: A serum marker of dengue disease via NS3 protease-mediated antibody cleavage.

Dengue poses a significant global public health threat, with diverse clinical manifestations due to complex interactions between the host and the pathogen. Recent reports have highlighted elevated serum-free light chain (FLC) levels in viral infectious diseases. Hence, our study aimed to investigate serum FLC levels in dengue patients. The findings revealed elevated serum λ FLCs, which were associated with the severity of dengue. Receiver operating characteristic curve (ROC) analysis demonstrated that λ FLCs may serve as a serum marker for identifying dengue disease (AUC: 0.7825, sensitivity: 80, specificity: 71.43) and classifying severe dengue (AUC: 0.8102, sensitivity: 75, specificity: 79.52). The viral protease, Dengue virus (DENV) nonstructural protein 3 (NS3), acts as a protease that cleaves viral polyproteins as well as host substrates. Therefore, we proposed that antibodies might be potential targets of NS3 protease, leading to an increase in FLCs. LC/MS-MS analysis confirmed that λ FLCs were the predominant products after antibody degradation by NS3 protease. Additionally, purified NS3 protease cleaved both human IgG and DENV2-neutralizing antibodies, resulting in the presence of λ FLCs. Moreover, NS3 protease administration in vitro led to a reduction in the neutralizing efficacy of DENV2-neutralizing antibodies. In summary, the elevated serum λ FLC levels effectively differentiate dengue patients from healthy individuals and identify severe dengue. Furthermore, the elevation of serum λ FLCs is, at least in part, mediated through NS3 protease-mediated antibody cleavage. These findings provide new insights for developing diagnostic tools and understanding the pathogenesis of DENV infection.

Utilizing Proteomic Approaches to Uncover the Neuroprotective Effects of ACE Inhibitors: Implications for Alzheimer's Disease Treatment.

Two types of angiotensin-converting enzyme (ACE) inhibitors, lisinopril and benazepril HCl, were tested in neuroblastoma cells and found to upregulate low-density lipoprotein-receptor-related protein 1B (LRP1B) and 14-3-3 protein zeta/delta. Additionally, benazepril HCl was found to increase the expression of calreticulin. The upregulation of these proteins by ACE inhibitors may contribute to the amelioration of cognitive deficits in Alzheimer's disease/dementia, as well as the clinically observed deceleration of functional decline in Alzheimer's patients. This discovery suggests that the supplementation of ACE inhibitors may promote neuronal cell survival independently of their antihypertensive effect. Overall, these findings indicate that ACE inhibitors may be a promising avenue for developing effective treatments for Alzheimer's disease.

The CD133 and CD34 cell types in human umbilical cord blood have the capacity to produce infectious dengue virus particles.

Although dengue virus (DENV) can establish infections in hematopoietic stem progenitor cells (HSPCs), there is little information on dengue virus persistent infection in CD34+ and CD133+ cell surface glycoproteins of hematopoietic stem cells (HSCs). CD34 and CD133 also function as cell-cell adhesion factors, which are present in umbilical cord blood (UCB). In this study, we sought to establish a persistent infection model of DENV infection in UCB using a prolonged period of infection lasting 30 days. Post-infection, the results exhibited a productive and non-productive phase of DENV production. Using a plaque assay, Western blot, and confocal microscopy, we demonstrated that CD133 and CD34 cells are target cells for DENV infection. Moreover, we showed that DENV particles can be recovered from the non-productive phase of DENV-infected CD34 and CD133 cells after co-incubation with Vero cells. We concluded that CD133 and CD34 retain their capacity to produce the infectious virus due to proliferation and their ability to repopulate, as deduced from a BrdU proliferation assay and flow cytometry analysis using t-distributed stochastic neighbor embedding. In summary, the platform to co-culture infected primitive HSCs from their non-productive phase onto Vero cells will give new insights into understanding the DENV dynamics in cell-to-cell transmission and reactivation of the virus.

Immune Response Related to Lymphadenopathy Post COVID-19 Vaccination.

Mass vaccination against coronavirus disease 2019 (COVID-19) is a global health strategy to control the COVID-19 pandemic. With the increasing number of vaccinations, COVID-19 vaccine-associated lymphadenopathy (C19-VAL) has been frequently reported. Current findings emphasize the characteristics of C19-VAL. The mechanism of C19-VAL is complicated to explore. Accumulated reports separately show that C19-VAL incidence is associated with receiver age and gender, reactive change within lymph nodes (LN), etc. We constructed a systematic review to evaluate the associated elements of C19-VAL and provide the mechanism of C19-VAL. Articles were searched from PubMed, Web of Science and EMBASE by using the processing of PRISMA. The search terms included combinations of the COVID-19 vaccine, COVID-19 vaccination and lymphadenopathy. Finally, sixty-two articles have been included in this study. Our results show that days post-vaccination and B cell germinal center response are negatively correlated with C19-VAL incidence. The reactive change within LN is highly related to C19-VAL development. The study results suggested that strong vaccine immune response may contribute to the C19-VAL development and perhaps through the B cell germinal center response post vaccination. From the perspective of imaging interpretation, it is important to carefully distinguish reactive lymph nodes from metastatic lymph node enlargement through medical history collection or evaluation, especially in patients with underlying malignancy.

Utilizing Proteomic Approach to Analyze Potential Antioxidant Proteins in Plant against Irradiation.

Gamma-ray irradiation is an effective and clean method of sterilization by inactivating microorganisms. It can also be applied to induce anti-oxidants for future application. In this study, the mung bean (Vigna radiata) was exposed to gamma-ray irradiation under the dose of 0, 5 or 10 kGy. With increasing irradiation doses, the concentrations of malondiadehyde decreased while the levels of total flavonoids and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity increased. It has been shown that consuming flavonoids can provide protective effects. In addition, proteomic analysis identified several proteins having anti-oxidant activities in the 5 kGy irradiated group. These proteins are Apocytochrome f, Systemin receptor SR 160, DELLA protein DWARF8, DEAD-box ATP-dependent RNA helicase 9, ζ-carotene desaturase (ZDS), and Floral homeotic protein AGAMOUS. Our findings indicate that plants contain a variety of phytochemicals and antioxidant proteins which may effectively prevent oxidative stress caused by irradiated peroxidation.

Mobilization of Hematopoietic Stem and Progenitor Cells during Dengue Virus Infection.

Hematopoietic stem and progenitor cells (HSPCs) mobilization is the movement of HSPCs from the bone marrow to the peripheral blood or tissue induced by stress. HSPC mobilization is a well-known response to protect the host during infection through urgent differentiation of HSPCs to immune cells. Dengue virus (DENV) infection is known to cause stress in infected humans and the mobilizing capacity of HSPCs during DENV infection in affected patients has not been fully investigated. Here, we investigated whether DENV infection can induce HSPC mobilization and if the mobilized HSPCs are permissive to DENV infection. White blood cells (WBCs) were collected from dengue patients (DENV+) and healthy donors and analyzed by flow cytometry and plaque assay. Elevated HSPCs levels were found in the WBCs of the DENV+ group when compared to the healthy group. Mobilization of HSPCs and homing markers (skin and gut) expression decreased as the patients proceeded from dengue without symptoms (DWoWS) to severe dengue (SD). Mobilizing HSPCs were not only permissive to DENV infection, but infectious DENV could be recovered after coculture. Our results highlight the need for further investigation into HSPC mobilization or alterations of hematopoiesis during viral infections such as DENV in order to develop appropriate countermeasures.

Antrodia cinnamomea Suppress Dengue Virus Infection through Enhancing the Secretion of Interferon-Alpha.

Dengue caused by dengue virus (DENV) is a mosquito-borne disease. Dengue exhibits a wide range of symptoms, ranging from asymptomatic to flu-like illness, and a few symptomatic cases may develop into severe dengue, leading to death. However, there are no effective and safe therapeutics for DENV infections. We have previously reported that cytokine expression, especially inflammatory cytokines, was altered in patients with different severities of dengue. Antrodia cinnamomea (A. cinnamomea) is a precious and endemic medical mushroom in Taiwan. It contains unique chemical components and exhibits biological activities, including suppressing effects on inflammation and viral infection-related diseases. According to previous studies, megakaryocytes can support DENV infection, and the number of megakaryocytes is positively correlated with the viral load in the serum of acute dengue patients. In the study, we investigated the anti-DENV effects of two ethanolic extracts (ACEs 1-2) and three isolated compounds (ACEs 3-5) from A. cinnamomea on DENV infection in Meg-01 cells. Our results not only demonstrated that ACE-3 and ACE-4 significantly suppressed DENV infection, but also reduced interleukin (IL)-6 and IL-8 levels. Moreover, the level of the antiviral cytokine interferon (IFN)-α was also increased by ACE-3 and ACE-4 in Meg-01 cells after DENV infection. Here, we provide new insights into the potential use of A. cinnamomea extracts as therapeutic agents against DENV infection. However, the detailed mechanisms underlying these processes require further investigation.

A Rare Adverse Effect of the COVID-19 Vaccine on Autoimmune Encephalitis.

Since countries commenced COVID-19 vaccination around the world, many vaccine-related adverse effects have been reported. Among them, short-term memory loss with autoimmune encephalitis (AE) was reported as a rare adverse effect. Since case numbers are limited, this brief report may draw the attention of the medical community to this uncommon adverse effect and serve as a reference for future vaccine improvement. However, given the high risk of adverse outcomes when infected with SARS-CoV-2 and the clearly favorable safety/tolerability profile of existing vaccines, vaccination is still recommended.

The Effects of Prior Mammography Screening on the Performance of Breast Cancer Detection in Taiwan.

The aim of this study was to investigate the influence of previous mammography screening on the performance of breast cancer detection. The screened women were divided into first-visit and follow-up groups for breast cancer screening. The positive predictive value (PPV), cancer detection rate (CDR), and recall rate were used to evaluate and analyze the overall screening performance among the two groups. Among them, 10,040 screenings (67.2%) were first visits and 4895 screenings (32.8%) were follow-up visits. The proportion of positive screening results for first-visit participants was higher than that for their follow-up counterparts (9.3% vs. 4.0%). A total of 98 participants (74 first-visit and 24 follow-up visit) were confirmed to have breast cancer. The PPV for positive mammography for women who underwent biopsy confirmation was 28.7% overall, reaching 35.8% for the follow-up visit group and 27.0% for the first-visit group. The CDR was 6.6 per 1000 overall, reaching 7.4 per 1000 for first-visit group and 4.9 per 1000 for the follow-up group. The overall recall rate was 7.9%, reaching 9.7% for the first-visit group and 4.2% for the follow-up group. The PPV is improved and the recall rate is decreased if prior mammography images are available for comparison when conducting mammography screening for breast cancer. By this study, we concluded that prior mammography plays an important role for breast cancer screening, while follow-up mammography may increase the diagnostic rate when compared to the prior mammography. We suggest that the public health authority can encourage subjects to undergo screenings in the same health institute where they regularly visit.

Hydrogels: Properties and Applications in Biomedicine.

Hydrogels are crosslinked polymer chains with three-dimensional (3D) network structures, which can absorb relatively large amounts of fluid. Because of the high water content, soft structure, and porosity of hydrogels, they closely resemble living tissues. Research in recent years shows that hydrogels have been applied in various fields, such as agriculture, biomaterials, the food industry, drug delivery, tissue engineering, and regenerative medicine. Along with the underlying technology improvements of hydrogel development, hydrogels can be expected to be applied in more fields. Although not all hydrogels have good biodegradability and biocompatibility, such as synthetic hydrogels (polyvinyl alcohol, polyacrylamide, polyethylene glycol hydrogels, etc.), their biodegradability and biocompatibility can be adjusted by modification of their functional group or incorporation of natural polymers. Hence, scientists are still interested in the biomedical applications of hydrogels due to their creative adjustability for different uses. In this review, we first introduce the basic information of hydrogels, such as structure, classification, and synthesis. Then, we further describe the recent applications of hydrogels in 3D cell cultures, drug delivery, wound dressing, and tissue engineering.

The Effects of Heterologous Immunization with Prime-Boost COVID-19 Vaccination against SARS-CoV-2.

Coronavirus Disease 2019 (COVID-19) pandemic, which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become the global challenge. Reaching global herd immunity will help end the COVID-19 pandemic. However, vaccine shortage and vaccine hesitancy are the obstacles to achieve global herd immunity against SARS-CoV-2. The current homologous vaccine regimen is experimentally switching to heterologous vaccination at several study sites. However, the reactogenicity of heterologous ChAdOx1-S and mRNA vaccination against SARS-CoV-2 is still unclear. We have conducted a systematic review to summarize the current findings on the safety and immunogenicity of this heterologous vaccination and elucidate their implications against SARS-CoV-2. This systematic review was conducted by the guidelines of PRISMA. Articles were searched from PubMed and other sources (MedRixv and Google scholar) starting from 1 January to 5 September 2021. The search term was heterologous ChAdOx1-S and BNT162b2 or mRNA-1273 vaccination. Our review found that participants with ChAdOx1/BNT162b2, ChAdOx1-S/mRNA-1273 or BNT162b2/ChAdOx1-S did not have the serious adverse events seen with homologous vaccination. Participants with the heterologous regimen (ChAdOx1/BNT162b2, ChAdOx1-S/mRNA-1273 or BNT162b2/ChAdOx1-S), compared with those with two doses of ChAdOx1-S, have shown a more robust immune responses against SARS-CoV-2, such as higher levels of responsive antibodies or increased numbers of spike-specific T-cells. Nevertheless, these immune responses were slightly diminished in the recipients of BNT162b2/ChAdOx1-S. Also, the safety study of heterologous ChAdOx1-S/mRNA vaccination was based on small populations. Further studies to enclose diverse categories, such as race/ethnicity or geography, may be necessary. Overall, the heterologous immunization with ChAdOX1-S and the mRNA vaccine may improve the vaccine shortage related slow pace of reaching herd immunity, especially using the heterologous immunization with ChAdOx1-S/BNT162b2.

Pulmonary Findings of [18F]FDG PET/CT Images on Asymptomatic COVID-19 Patients.

During the coronavirus disease 2019 (COVID-19) pandemic, several case studies demonstrated that many asymptomatic patients with COVID-19 underwent fluorine-18 fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) examination for various indications. However, there is a lack of literature to characterize the pattern of [18F]FDG PET/CT imaging on asymptomatic COVID-19 patients. Therefore, a systematic review to analyze the pulmonary findings of [18F]FDG PET/CT on asymptomatic COVID-19 patients was conducted. This systematic review was performed under the guidelines of PRISMA. PubMed, Medline, and Web of Science were used to search for articles for this review. Articles with the key words: "asymptomatic", "COVID-19", "[18F]FDG PET/CT", and "nuclear medicine" were searched for from 1 January 2020 to 20 May 2021. Thirty asymptomatic patients with COVID-19 were included in the eighteen articles. These patients had a mean age of 62.25 ± 14.85 years (male: 67.71 ± 12.00; female: 56.79 ± 15.81). [18F]FDG-avid lung lesions were found in 93.33% (28/30) of total patients. The major lesion was [18F]FDG-avid multiple ground-glass opacities (GGOs) in the peripheral or subpleural region in bilateral lungs, followed by the consolidation. The intensity of [18F]FDG uptake in multiple GGOs was 5.605 ± 2.914 (range from 2 to 12) for maximal standardized uptake value (SUVmax). [18F]FDG-avid thoracic lymph nodes (LN) were observed in 40% (12/40) of the patients. They mostly appeared in both mediastinal and hilar regions with an SUVmax of 5.8 ± 2.93 (range from 2.5 to 9.6). The [18F]FDG uptake was observed in multiple GGOs, as well as in the mediastinal and hilar LNs. These are common patterns in PET/CT of asymptomatic patients with COVID-19.

Evidence that hematopoietic stem cells in human umbilical cord blood is infectable by dengue virus: proposing a vertical transmission candidate.

BACKGROUND: Recent studies have shown that dengue virus (DENV) can efficiently infect bone marrow hematopoietic stem cells (HSCs) as well as the placenta of pregnant women. Although mother-to-infant vertical transmission of DENV through the placenta has been well documented, the evidence of cell-associated vertical transmission is still unknown. Whether DENV can infect umbilical cord blood (UCB) cells before reaching the fetus remains to be explored. Here, we proposed that human UCB cells were permissive to the DENV infection and DENV infected CD133+ and CD34+ HSCs are reservoir of the virus that could be reactivated upon re-culturing in suitable cells. METHODS: Human UCB cells were freshly obtained and subjected to DENV infection. Multicolor flow cytometry (MFCM) was used to demonstrate the phenotypes of the infected HSC populations. Immunofluorescence analysis (IFA) and T-distributed Stochastic Neighbor Embedding (t-SNE) were used to show the association of the DENV antigen, non-structural protein1 (NS1) with HSCs. KEY FINDINGS: UCB cells were highly permissive to DENV infection. DENV altered the phenotype of the infected HSC population, increased the expression of HSCs, and affected the balance of transcription factors (TFs, GATA1/2/3). IFA revealed the association of the DENV antigen, non-structural protein1 (NS1), with CD34+ and CD133+ cells. T-distributed Stochastic Neighbor Embedding (t-SNE) analysis revealed heterogeneity in the distribution of CD133+NS1+, and CD34+ NS1+ cells. DENV particles were recovered from CD133+ and CD34+ cells even when virus production in the supernatant was negligible. SIGNIFICANCE: We predict that infection of CD133+ and CD34+ cells in the UCB serve as reservoirs for the amplification of DENV in UCB prior to the virus reaching the fetus and facilitate vertical transmission.

Cytokine Signature of Dengue Patients at Different Severity of the Disease.

Clinical presentations of dengue fever (DF) are diverse and non-specific, causing unpredictable progression and outcomes. Its progression and severity have been associated with cytokine levels alteration. In this study, dengue patients were classified into groups following the 2009 WHO dengue classification scheme to investigate the cytokine signature at different severity of the disease: dengue without warning sign symptoms (A); dengue with warning signs (B); severe dengue (C); other fever (OF) and healthy (Healthy). We analyzed 23 different cytokines simultaneously, namely IL-1b, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-17A, IL-33, CD14, CD54, CD62E, CD62L, CD62p, CD106, CD121b, CD154, CD178, GM-CSF, IFN-g, MIF, ST2 and TNF from patients admitted to National Cheng Kung University Hospital during the 2015 Taiwan dengue outbreak. Cytokines TNF, CD54, CD62E, CD62L, CD62P, GM-CSF, IL-1b, IL-2, IL-6, IL-8, IL-10, IL-12p70, IL-17A, INF-g and MIF were elevated while CD106, CD154, IL-4 and L-33 were decreased when compared to the control. IL-10 demonstrated to be a potential diagnostic marker for DF (H and A group; AUC = 0.944, H and OF group; AUC = 0.969). CD121b demonstrated to be predictive of the SD (A and B group; AUC = 0.744, B and C group; AUC = 0.775). Our results demonstrate the cytokine profile changes during the progression of dengue and highlight possible biomarkers for optimizing effective intervention strategies.

Chloroquine and Hydroxychloroquine: Efficacy in the Treatment of the COVID-19.

Chloroquine (CQ) and its derivative, hydroxychloroquine (HCQ), have attracted wide attention for treating coronavirus disease 2019 (COVID-19). However, conflicting outcomes have been found in COVID-19 clinical trials after treatment with CQ or HCQ. To date, it remains uncertain whether CQ and HCQ are beneficial antiviral drugs for combating COVID-19. We performed a systematic review to depict the efficacy of CQ or HCQ for the treatment of COVID-19. The guidelines of PRISMA were used to conduct this systematic review. We searched through articles from PubMed, Web of Science and other sources that were published from 1 January 2020 to 31 October 2020. The search terms included combinations of human COVID-19, CQ, and HCQ. Eleven qualitative articles comprising of four clinical trials and seven observation studies were utilized in our systematic review. The analysis shows that CQ and HCQ do not have efficacy in treatment of patients with severe COVID-19. In addition, CQ and HCQ have caused life-threatening adverse reactions which included cardiac arrest, electrocardiogram modification, and QTc prolongation, particularly during the treatment of patients with severe COVID-19. Our systematic review suggested that CQ and HCQ are not beneficial antiviral drugs for curing patients with severe COVID-19. The treatment effect of CQ and HCQ is not only null but also causes serious side effects, which may cause potential cardiotoxicity in severe COVID-19 patients.

Low seroprevalence of Zika virus infection among adults in Southern Taiwan.

BACKGROUND: We recently conducted a serosurvey of newly arrived workers in Taiwan from four Southeast Asian countries which revealed that 1% of the migrant workers had laboratory-confirmed recent Zika virus (ZIKV) infection. Taiwan, where Aedes mosquitoes are prevalent, has a close relationship with Southeast Asian countries. Up to now, 21 imported cases of ZIKV infection have been reported in Taiwan, but there has been no confirmed indigenous case. The aim of this serosurvey was to assess whether there was unrecognized ZIKV infections in Taiwan. METHODS: A total of 212 serum samples collected in a cross-sectional seroepidemiologic study conducted during the end of the 2015 dengue epidemic in Tainan, Taiwan, were analyzed. Anti-ZIKV IgM and IgG were tested using commercial enzyme-linked immunosorbent assays (ELISAs). Plaque reduction neutralization tests (PRNTs) for ZIKV and four dengue virus (DENV) serotypes were performed for samples with positive anti-ZIKV antibodies. A confirmed case of ZIKV infection was defined by ZIKV PRNT90 titer ratio ≥ 4 compared to four DENV serotypes. RESULTS: The mean age of the 212 participants was 54.0 years (standard deviation 13.7 years), and female was predominant (67.0%). Anti-ZIKV IgM and IgG were detected in 0 (0%) and 9 (4.2%) of the 212 participants, respectively. For the 9 samples with anti-ZIKV IgG, only 1 sample had 4 times higher ZIKV PRNT90 titers compared to PRNT90 titers against four dengue virus serotypes; this individual denied having traveled abroad. CONCLUSIONS: The results suggest that undetected indigenous ZIKV transmission might have occurred in Taiwan. The findings also suggest that the threat of epidemic transmission of ZIKV in Taiwan does exist due to extremely low-level of herd immunity. Our study also indicates that serological tests for ZIKV-specific IgG remain a big challenge due to cross-reactivity, even in dengue non-endemic countries.

Identification and characterization of permissive cells to dengue virus infection in human hematopoietic stem and progenitor cells.

BACKGROUND: Dengue virus (DENV) is a significant threat to public health in tropical and subtropical regions, where the frequency of human migration is increasing. Transmission of DENV from donors to recipients after hematopoietic stem cell transplantation has been steadily described. However, the underlying mechanisms remain unclear. STUDY DESIGN AND METHODS: Freshly isolated bone marrow (BM) was subjected to DENV infection, followed by multicolor fluorescence-activated cell sorting (FACS) analysis. Virus in supernatants was collected and analyzed by plaque assay. RESULTS: DENV-1 to DENV-4 could effectively infect freshly obtained BM and produced infectious virus. DENV infection did not change the quantitative population of hematopoietic stem and progenitor cells (HSPCs), megakaryocytic progenitor cells (MkPs) and megakaryocytes. Additionally, DENV antigen, nonstructural protein 1, was enriched in HSPCs and MkPs of DENV infected marrow cells. CD34+, CD133+, or CD61+ cells sorted out from BM were not only the major contributing targets facilitating the DENV infection directly but also facilitated the spread of DENV into other cells when cocultured. CONCLUSION: Results suggest that DENV can efficiently infect HSPCs, which might jeopardize the recipients if DENV-infected cells were subsequently used. We therefore raise the need for DENV screening for both the donors and recipients of hematopoietic stem cell transplantation, especially for donors exposed to endemic areas, to mitigate DENV infection in immunocompromised recipients.

Seroepidemiology of dengue virus infection among adults during the ending phase of a severe dengue epidemic in southern Taiwan, 2015.

BACKGROUND: A severe dengue epidemic occurred in 2015 which resulted in over 22,000 laboratory-confirmed cases. A cross-sectional seroprevalence study was conducted during the ending phase of this epidemic to evaluate the true incidence of dengue virus (DENV) infection and the level of herd immunity. METHODS: Adult residents in three administrative districts with high dengue incidence were recruited; workers in two districts with intermediate dengue incidence were also recruited for comparison. DENV-specific IgM and IgG were tested using commercial enzyme-linked immunosorbent assays. DENV RNA was detected using commercial quantitative real-time reverse transcriptase polymerase chain reaction assay. Univariate and multivariate logistic regressions were performed to identify risk factors for recent and past DENV infection. RESULTS: The overall seroprevalence of anti-DENV IgM and IgG in 1391 participants was 6.8 and 17.4%, respectively. The risk of recent DENV infection increased with age, with the elderly having the highest risk of infection. Living in areas with high incidence of reported dengue cases and having family members being diagnosed with dengue in 2015 were also independent risk factors for recent DENV infection. One sample was found to have asymptomatic viremia with viral load as high as 105 PFU/ml. CONCLUSIONS: Comparing the seroprevalence of anti-DENV IgM with the incidence of reported dengue cases in 2015, we estimated that 1 out of 3.7 dengue infections were reported to the surveillance system; widespread use of rapid diagnostic tests might contribute to this high reporting rate. The results also indicate that the overall herd immunity remains low and the current approved Dengvaxia® is not quite suitable for vaccination in Taiwan.

Seroprevalence of Zika and Dengue Virus Antibodies among Migrant Workers, Taiwan, 2017.

A serosurvey of 600 workers newly arrived in Taiwan from 4 Southeast Asia countries showed that 18 (3%) were positive for Zika virus IgM; 6 (1%) fulfilled the World Health Organization criteria for laboratory-confirmed recent Zika virus infection. The incidence of Zika virus infection in Southeast Asia might be underestimated.