Covert COVID-19 and false-positive dengue serology in Singapore

Dengue-COVID-19 coinfection: the first reported case in the Philippines

The rainy season in the Philippines is from June to October; this is when the number of dengue cases typically increases. In 2020 during this time, the world was facing the threat of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Coronavirus disease 2019 (COVID-19) and dengue viral infections have similar presentations and laboratory findings, including fever and thrombocytopenia, and there have been reports of coinfection with SARS-CoV-2 and arthropod-borne virus. Here, we report a case of SARS-CoV-2–dengue virus coinfection in the Philippines in a female aged 62 years, whose early symptom was fever and who was positive for SARS-CoV-2 and positive for dengue. Early recognition of such coinfection is important so that proper measures can be taken in the management of the patient.

Potential Misdiagnosis between COVID-19 and Dengue Infection Using Rapid Serological Test

The coronavirus disease 2019 (COVID-19) pandemic that has a significant rapid transmission is an international public health concern. Several dengue-endemic countries reported similar clinical and laboratory features between COVID-19 and dengue in the early incubation period, and thus discerning the infection is difficult. As a dengue-endemic country, Indonesia also poses the same challenge during the COVID-19 outbreak. This current study analyzed the IgG and IgM profiles from COVID-19 patients by using a serological SARS-CoV-2 and dengue rapid test. In addition, 38 sera from healthy individuals (pre-COVID-19 date) were analyzed using a dengue rapid test. Among 120 samples, 4 samples indicated dengue IgG positive. However, IgM, NS1, and RT-PCR analyses showed negative results. Interestingly, regarding seropositivity of NS1 and DENV IgG from healthy individuals (pre COVID-19 infection), two samples were positive DENV IgG, while one of them was positive NS1. This suggested that in the dengue-endemic area, many people have already experienced dengue and have immunity against dengue virus. There is also the possibility of antibody cross-reactivity between COVID-19 and dengue infection. This also emphasizes the high demand for a rapid method with high sensitivity and specificity that can distinguish between SARS-CoV-2 and dengue.

Developing an efficient deep neural network for automatic detection of COVID-19 using chest X-ray images

The novel coronavirus (COVID-19) could be described as the greatest human challenge of the 21st century. The development and transmission of the disease have increased mortality in all countries. Therefore, a rapid diagnosis of COVID-19 is necessary to treat and control the disease. In this paper, a new method for the automatic identification of pneumonia (including COVID-19) is presented using a proposed deep neural network. In the proposed method, the chest X-ray images are used to separate 2–4 classes in 7 different and functional scenarios according to healthy, viral, bacterial, and COVID-19 classes. In the proposed architecture, Generative Adversarial Networks (GANs) are used together with a fusion of the deep transfer learning and LSTM networks, without involving feature extraction/selection for classification of pneumonia. We have achieved more than 90% accuracy for all scenarios except one and also achieved 99% accuracy for separating COVID-19 from healthy group. We also compared our deep proposed network with other deep transfer learning networks (including Inception-ResNet V2, Inception V4, VGG16 and MobileNet) that have been recently widely used in pneumonia detection studies. The results based on the proposed network were very promising in terms of accuracy, precision, sensitivity, and specificity compared to the other deep transfer learning approaches. Depending on the high performance of the proposed method, it can be used during the treatment of patients.

A single snapshot multiplex immunoassay platform utilizing dense test lines based on engineered beads

Co-circulation of coronavirus disease 2019 (COVID-19) and dengue fever has been reported. Accurate and timely multiplex diagnosis is required to prevent future pandemics. Here, we developed an innovative microfluidic chip that enables a snapshot multiplex immunoassay for timely on-site response and offers unprecedented multiplexing capability with an operating procedure similar to that of lateral flow assays. An open microchannel assembly of individually engineered microbeads was developed to construct nine high-density test lines, which can be imaged in a 1 mm² field-of-view. Thus, simultaneous detection of multiple antibodies would be achievable in a single high-resolution snapshot. Next, we developed a novel pixel intensity-based imaging process to distinguish effective and non-specific fluorescence signals, thereby improving the reliability of this fluorescence-based immunoassay. Finally, the chip specifically identified and classified random combinations of arbovirus (Zika, dengue, and chikungunya viruses) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies within 30 min. Therefore, we believe that this snapshot multiplex immunoassay chip is a powerful diagnostic tool to control current and future pandemics.

Severe Thrombocytopenia in COVID-19: A Conundrum in Dengue-endemic Areas

Thrombocytopenia in coronavirus disease-2019 (COVID-19) can be attributed to multiple factors. Most often it is disease related. It is usually mild and if severe often associated with severe COVID-19 disease. It can also be due to drugs (Remdesivir, Tocilizumab) or coinfection with other viruses. Here we report two cases of severe thrombocytopenia in COVID-19 due to dengue coinfection. Most often the thrombocytopenia in dengue is self-resolving, and a careful “wait and watch” should suffice unlike COVID-19, where steroids can help if the cytopenia is due to cytokine storm or immune-mediated effects.

COVID-19 and Tropical Infection: Complexity and Concurrence

COVID-19 is a newly emerging pandemic caused by a novel coronavirus. After its first report in China in December 2019, the disease already spread and affected more than 200 countries worldwide. It correlates with different phenotypes ranging from an acute febrile illness to severe respiratory problems. Often, patients with COVID-19 suffer from metabolic disorders, and this can result in a more severe clinical course. COVID-19 might also co-occur with other common diseases in different settings. In tropical countries, COVID-19 has already affected thousands of local populations. Tropical diseases such as dengue and tuberculosis can modify the clinical presentation of COVID-19 and result in difficulty in the diagnosis and treatment of the patients. The complexity of concurrence between COVID-19 and tropical diseases is, thus, a matter of concern in tropical medicine. This chapter is devoted to discussing problems surrounding the management of COVID-19 in tropical countries. To exemplify the effects of COVID-19 on tropical countries, the authors would show how COVID-19 has affected Indochina, a large tropical area.

Successful management of dengue in renal transplant recipients: A retrospective cohort from a single center

INTRODUCTION

The literature on dengue infection in renal transplant recipients has shown wide diversity in clinical presentation and outcome. The objective of this study was to report the clinical profile, short-term and long-term outcomes of dengue among renal transplant recipients.

METHODS

A total of 59 post-transplant dengue suspected cases were admitted from July 2019 to April 2020 of which 31 had confirmed dengue infection. The clinical and laboratory profile of the confirmed dengue cases (n = 31) were compared with non-dengue cases (n = 28).

RESULTS

Among the clinical and laboratory features retro-orbital pain, conjunctival redness, thrombocytopenia on admission, and absence of arthralgia were significantly associated with dengue compared to non-dengue cases. No mortality was observed in the dengue cases. Allograft dysfunction, acute rejection and graft losses were identified in 64.5% (n = 20), 6.4% (n = 2) and 6.4% (n = 2) dengue cases respectively. No rejection or graft losses were observed in 1-year follow-up.

CONCLUSIONS

We report a differential clinical profile for dengue in transplant settings which will aid in the diagnosis. We also report successful management of dengue infection in renal transplant recipients with the majority having allograft dysfunction. A long-term follow-up of the cohort was uneventful.

Diagnostic accuracy of the WHO clinical definitions for dengue and implications for surveillance: A systematic review and meta-analysis

Background

Dengue is the world’s most common mosquito-borne virus but remains diagnostically challenging due to its nonspecific presentation. Access to laboratory confirmation is limited and thus most reported figures are based on clinical diagnosis alone, the accuracy of which is uncertain. This systematic review assesses the diagnostic accuracy of the traditional (1997) and revised (2009) WHO clinical case definitions for dengue fever, the basis for most national guidelines.

Methodology/Principal findings

PubMed, EMBASE, Scopus, OpenGrey, and the annual Dengue Bulletin were searched for studies assessing the diagnostic accuracy of the unmodified clinical criteria. Two reviewers (NR/SL) independently assessed eligibility, extracted data, and evaluated risk of bias using a modified QUADAS-2. Additional records were found by citation network analysis. A meta-analysis was done using a bivariate mixed-effects regression model. Studies that modified criteria were analysed separately. This systematic review protocol was registered on PROSPERO (CRD42020165998). We identified 11 and 12 datasets assessing the 1997 and 2009 definition, respectively, and 6 using modified criteria. Sensitivity was 93% (95% CI: 77–98) and 93% (95% CI: 86–96) for the 1997 and 2009 definitions, respectively. Specificity was 29% (95% CI: 8–65) and 31% (95% CI: 18–48) for the 1997 and 2009 definitions, respectively. Diagnostic performance suffered at the extremes of age. No modification significantly improved accuracy.

Conclusions/Significance

Diagnostic accuracy of clinical criteria is poor, with significant implications for surveillance and public health responses for dengue control. As the basis for most reported figures, this has relevance to policymakers planning resource allocation and researchers modelling transmission, particularly during COVID-19.

Dengue is the most common mosquito-borne disease worldwide, with half the world’s population living in at-risk areas, yet it remains difficult to diagnose. Existing laboratory tests have highly variable performance, and access to them remains limited in most dengue-endemic regions. Thus, most dengue cases are diagnosed on clinical criteria alone. While national guidelines vary, most are based on the WHO case definitions, produced in 1997 and revised in 2009. Here, we assess the diagnostic accuracy of both definitions and find that they have good sensitivity but poor specificity, particularly problematic given the co-circulation of multiple febrile illnesses in these regions. This makes it difficult for policymakers and researchers to model transmission, assess the introduction of new pathogens to a region, and correctly prioritise control measures and vaccination programmes in a region-specific manner. This is exacerbated by the ongoing COVID-19 pandemic, given rising cases of both diseases and the stark difference in necessary control measures. As such, improvements in dengue diagnostic and reporting practice are increasingly urgent. This could be achieved by incorporating symptom absence into clinical criteria, weighting symptoms depending on strength of association with dengue or timing within disease course, or using clinical criteria to allocate limited testing resources in borderline cases.

Rapid diagnostic tests for the detection of recent dengue infections: An evaluation of six kits on clinical specimens

Introduction

Early and rapid confirmation of dengue infections strengthens disease surveillance program and are critical to the success of vector control measures. Rapid diagnostics tests (RDTs) are increasingly used to confirm recent dengue infections due to their ease of use and short turnaround time for results. Several studies undertaken in dengue-endemic Southeast Asia have reported the performance of RDTs against enzyme-linked immunosorbent assay (ELISA), reverse transcriptase polymerase chain reaction (RT-PCR) and virus isolation methods. However, few studies have compared multiple RDTs for the detection of dengue NS1 antigen and IgM antibody in a single combo cassette. We evaluated six RDTs in Singapore for their utility in routine clinical testing to detect recent dengue infections.

Methods

The evaluation comprised two phases. The first phase sought to determine each RDT’s specificity to dengue NS1 and IgM using zika and chikungunya virus supernatant and zika convalescent samples. RDTs that cross-reacted with zika or chikungunya were not further tested in phase 2. The second phase sought to determine the sensitivity and specificity of the remaining RDTs to dengue NS1 and IgM using pre-characterised dengue specimens and non-dengue/chikungunya febrile clinical specimens.

Results

None of the RDTs cross-reacted with zika IgM in Phase 1. Truquick and Quickprofile cross reacted with zika and chikungunya viruses and were not evaluated thereafter. Standard Q had the highest dengue NS1 and IgM sensitivity at 87.0% and 84.3% respectively whereas Bioline (68.5%) and Multisure (58.3%) had the lowest dengue NS1 and IgM sensitivity respectively. Combining dengue NS1/IgM detection results greatly improved the RDT ability to detect recent dengue infection; Standard Q had the highest sensitivity at 99.1% while Multisure had the lowest at 92.6%. All the RDTs were highly specific for dengue NS1 and IgM (96.7% to 100%). All the RDTs had high positive predictive values (98.4% to 100%) for NS1, IgM and combined NS1/IgM parameters whereas Standard Q had the highest negative predictive values at 68.2% (NS1), 63.8% (IgM) and 96.8% (NS1/IgM). For the RDTs, detection of NS1 declined from acute to convalescent phase of illness whereas IgM detection rate gradually increased over time.

Conclusion

In our study, several RDTs were evaluated for their diagnostic accuracy and capability in detecting recent dengue infection. Standard Q demonstrated a high degree of diagnostic accuracy and capability in the detection of NS1 and IgM biomarkers. RDTs can provide rapid and accurate confirmation of recent dengue infections and augment dengue surveillance and control programmes. Further studies are required to assess the usefulness of these RDTs in other epidemiology settings.

COVID-19, Chikungunya, Dengue and Zika Diseases: An Analytical Platform Based on MALDI-TOF MS, IR Spectroscopy and RT-qPCR for Accurate Diagnosis and Accelerate Epidemics Control

COVID-19 and arboviruses (ARBOD) epidemics co-occurrence is a great concern. In tropical and subtropical regions, ARBOD diseases such as chikungunya, dengue, and Zika are frequent. In both COVID-19 and ARBOD cases, an accurate diagnosis of infected patients is crucial to promote adequate treatment and isolation measures in COVID-19 cases. Overlap of clinical symptoms and laboratory parameters between COVID-19 and ARBOD present themselves as an extra challenge during diagnosis. COVID-19 diagnosis is mainly performed by quantitative reverse polymerase chain reaction (RT-qPCR), while ARBOD diagnosis is performed by serology, detection of antigen or antibody, and molecular diagnosis. In this review, the epidemiologic profile of arboviruses and SARS-CoV-2 is analyzed, and potential risks of symptom overlap is addressed. The implementation of an analytical platform based on infrared (IR) spectroscopy, MALDI-TOF mass spectrometry, and RT-qPCR is discussed as an efficient strategy for a fast, robust, reliable, and cost-effective diagnosis system even during the co-occurrence of virus outbreaks. The spectral data of IR spectroscopy and MALDI-TOF MS obtained from COVID-19 infected and recovered patients can be used to build up an integrated spectral database. This approach can enable us to determine quickly the groups that have been exposed and have recovered from COVID-19 or ARBOD, avoiding misdiagnoses.

Coronavirus disease 2019 and dengue: two case reports

Background

The pandemic of this century has overwhelmed the healthcare systems of affected countries, and all resources have been diverted to coronavirus disease 2019. At the onset, coronavirus disease 2019 can present as any other acute febrile undifferentiated illness. In tropical regions, clinicians are increasingly challenged to differentiate these febrile illnesses without the use of diagnostics. With this pandemic, many of these tropical diseases are neglected and go underreported. Dengue is holoendemic in the Maldives, and dengue viruses circulate throughout the year. Reports about coinfections with dengue virus and severe acute respiratory syndrome coronavirus 2 are scarce, and the outcome and the dynamics of the disease may be altered in the presence of coinfection. We have described the clinical manifestation and serial laboratory profile, and highlighted the atypical findings uncommon in dengue infection.

Case presentation

Case 1 was a 39-year old Asian male, presented on day 6 of dengue infection with warning signs. Reverse transcription polymerase chain reaction for severe acute respiratory syndrome coronavirus 2 that was done as per hospital protocol was found to be positive. Case 2 was a 38-year old Asian male, was admitted on day 5 of illness with symptoms of acute respiratory infection with positive reverse transcription polymerase chain reaction for severe acute respiratory syndrome coronavirus 2. Evaluation of progressive leukopenia and thrombocytopenia showed positive dengue serology.

Conclusion

Clinicians must be conscientious when working on the differential diagnosis of possible tropical diseases in cases of coronavirus disease 2019, specifically, when patients develop hemoconcentration, thrombocytopenia, and transaminitis with elevated expression of aspartate higher than alanine transaminase, which is frequently observed in dengue infection. Caution must be taken during the administration of intravenous fluids when treating patients with coronavirus disease 2019 and dengue coinfection, as coronavirus disease 2019 patients are more prone to develop pulmonary edema. Timely diagnosis and appropriate management are essential to avoid the devastating complications of severe forms of dengue infection. It is important to repeat and reconfirm the dengue serology in coronavirus disease 2019 patients to avoid false positivity. Diligence and care must be taken not to neglect other endemic tropical diseases in the region during the present pandemic.

Assessment of dengue and COVID-19 antibody rapid diagnostic tests cross-reactivity in Indonesia

Background

The coronavirus disease 2019 (COVID-19) pandemic remains ongoing around the world, including in areas where dengue is endemic. Dengue and COVID-19, to some extent, have similar clinical and laboratory features, which can lead to misdiagnosis, delayed treatment and patient’s isolation. The use of rapid diagnostic tests (RDT) is easy and convenient for fast diagnosis, however there may be issues with cross-reactivity with antibodies for other pathogens.

Methods

We assessed the possibility of cross-reactivity between SARS-CoV-2 and dengue antibodies by: (1) testing five brands of COVID-19 IgG / IgM RDTs on 60 RT-PCR-confirmed dengue samples; (2) testing 95 RT-PCR-confirmed COVID-19 samples on dengue RDT; and (3) testing samples positive for COVID-19 IgG and/or IgM on dengue RDT.

Results

We observed a high specificity across all five brands of COVID-19 RDTs, ranging from 98.3 to 100%. Out of the confirmed COVID-19 samples, one patient tested positive for dengue IgM only, another tested positive for dengue IgG only. One patient tested positive for dengue IgG, IgM, and NS1, suggesting a co-infection. In COVID-19 IgG and/or IgM samples, 6.3% of COVID-19 IgG-positive samples also tested positive for dengue IgG, while 21.1% of COVID-19 IgM-positive samples also tested positive for dengue IgG.

Conclusion

Despite the high specificity of the COVID-19 RDT, we observed cross-reactions and false-positive results between dengue and COVID-19. Dengue and COVID-19 co-infection was also found. Health practitioners in dengue endemic areas should be careful when using antibody RDT for the diagnosis of dengue during the COVID-19 pandemic to avoid misdiagnosis.

Computational approach to decipher cellular interactors and drug targets during co-infection of SARS-CoV-2, Dengue, and Chikungunya virus

The world is reeling under severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, and it will be frightening if compounded by other co-existing infections. The co-occurrence of the Dengue virus (DENV) and Chikungunya virus (CHIKV) has been into existence, but recently the co-infection of DENV and SARS-CoV-2 has been reported. Thus, the possibility of DENV, CHIKV, and SARS-CoV-2 co-infection could be predicted in the future with enhanced vulnerability. It is essential to elucidate the host interactors and the connected pathways to understand the biological insights. The in silico approach using Cytoscape was exploited to elucidate the common human proteins interacting with DENV, CHIKV, and SARS-CoV-2 during their probable co-infection. In total, 17 interacting host proteins were identified showing association with envelope, structural, non-structural, and accessory proteins. Investigating the functional and biological behaviour using PANTHER, UniProtKB, and KEGG databases uncovered their association with several cellular pathways including, signaling pathways, RNA processing and transport, cell cycle, ubiquitination, and protein trafficking. Withal, exploring the DrugBank and Therapeutic Target Database, total seven druggable host proteins were predicted. Among all integrin beta-1, histone deacetylase-2 (HDAC2) and microtubule affinity-regulating kinase-3 were targeted by FDA approved molecules/ drugs. Furthermore, HDAC2 was predicted to be the most significant target, and some approved drugs are available against it. The predicted druggable targets and approved drugs could be investigated to obliterate the identified interactions that could assist in inhibiting viral infection.

Covid-19 and dengue: Double punches for dengue-endemic countries in Asia

The coronavirus disease 2019 (Covid-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is an international public health crisis with devastating effects. In particular, this pandemic has further exacerbated the burden in tropical and subtropical regions of the world, where dengue fever, caused by dengue virus (DENV), is already endemic to the population. The similar clinical manifestations shared by Covid-19 and dengue fever have raised concerns, especially in dengue-endemic countries with limited resources, leading to diagnostic challenges. In addition, cross-reactivity of the immune responses in these infections is an emerging concern, as pre-existing DENV-antibodies might potentially affect Covid-19 through antibody-dependent enhancement. In this review article, we aimed to raise the issue of Covid-19 and dengue fever misdiagnosis, not only in a clinical setting but also with regards to cross-reactivity between SARS-CoV-2 and DENV antibodies. We also have discussed the potential consequences of overlapping immunological cascades between dengue and Covid-19 on disease severity and vaccine development.

Impact of concurrent epidemics of dengue, chikungunya, zika, and COVID-19

INTRODUCTION:

This study evaluated the epidemiological implications of arbovirus infections and coronavirus disease (COVID-19) co-occurrences in Espírito Santo, Brazil.

METHODS:

This ecological study of dengue, chikungunya, zika, and COVID-19 was performed from January 1 to July 31, 2020.

RESULTS:

Espírito Santo registered 44,614, 8,092, 3,138, and 91,483 cases of dengue, chikungunya, zika, and COVID-19, respectively (January-July, 2020). In the 27 and four municipalities with a high incidence of dengue and chikungunya, respectively, the incidence of COVID-19 was 647.0-3,721.7 and 1,787.2-3,403.0 cases per 100,000 inhabitants, respectively.

CONCLUSIONS:

Espírito Santo experienced an overlap of epidemics, especially in urban areas.

Case Report: Severe COVID-19 and Dengue in an Indonesian Infant

We report a case of a 10-month infant with dual severe infection of COVID-19 and dengue fever who was admitted to the hospital with an influenza-like illness. The patient experienced severe conditions of COVID-19 and dengue fever with shock followed by disseminated intravascular coagulation. The standard of COVID-19 care was given coupled with fluid resuscitation and blood transfusion. The pitfalls of this case are how to differentiate the clinical manifestation of dengue fever in a patient with confirmed COVID-19; the difficulty to monitor the dengue course of illness of the patient in the COVID-19 isolation room; and to differentiate the severe dengue from the multisystem inflammatory syndrome-C when the patient was in critical condition. The infant recovered without sequale, but the management of new probable cases must be improved more thoroughly, especially during dengue peak period in tropical and developing countries such as Indonesia.

CovidCTNet: an open-source deep learning approach to diagnose covid-19 using small cohort of CT images

Coronavirus disease 2019 (Covid-19) is highly contagious with limited treatment options. Early and accurate diagnosis of Covid-19 is crucial in reducing the spread of the disease and its accompanied mortality. Currently, detection by reverse transcriptase-polymerase chain reaction (RT-PCR) is the gold standard of outpatient and inpatient detection of Covid-19. RT-PCR is a rapid method; however, its accuracy in detection is only ~70-75%. Another approved strategy is computed tomography (CT) imaging. CT imaging has a much higher sensitivity of ~80-98%, but similar accuracy of 70%. To enhance the accuracy of CT imaging detection, we developed an open-source framework, CovidCTNet, composed of a set of deep learning algorithms that accurately differentiates Covid-19 from community-acquired pneumonia (CAP) and other lung diseases. CovidCTNet increases the accuracy of CT imaging detection to 95% compared to radiologists (70%). CovidCTNet is designed to work with heterogeneous and small sample sizes independent of the CT imaging hardware. To facilitate the detection of Covid-19 globally and assist radiologists and physicians in the screening process, we are releasing all algorithms and model parameter details as open-source. Open-source sharing of CovidCTNet enables developers to rapidly improve and optimize services while preserving user privacy and data ownership.

Co-epidemics: have measures against COVID-19 helped to reduce Lassa fever cases in Nigeria?

While the coronavirus disease 2019 (COVID-19) pandemic has multiple devastating public health and socio-economic effects across the world, Nigeria along with other West African countries is simultaneously faced with a recurrent Lassa fever epidemic. The complicating scenario is the similarity in the clinical manifestation of COVID-19 and Lassa fever, making the misdiagnosis of the initial presentation of both diseases a significant risk with an increased likelihood of co-infection. However, the strict implementation of COVID-19 infection prevention and control measures across Nigeria after the initial outbreaks concurrently resulted in the reduction of Lassa fever cases. The abrupt change in the behaviour of Lassa fever epidemiological data, which are attributable to the implementation of COVID-19 infection prevention and control measures at the national, sub-national and community levels, requires detailed investigation during and after the COVID-19 epidemic to elucidate the interactions and evolutionary dynamics of Lassa fever cases in Nigeria.

Evaluation of the number of undiagnosed infected in an outbreak using source of infection measurements

In times of outbreaks, an essential requirement for better monitoring is the evaluation of the number of undiagnosed infected individuals. An accurate estimate of this fraction is crucial for the assessment of the situation and the establishment of protective measures. In most current studies using epidemics models, the total number of infected is either approximated by the number of diagnosed individuals or is dependent on the model parameters and assumptions, which are often debated. We here study the relationship between the fraction of diagnosed infected out of all infected, and the fraction of infected with known contaminator out of all diagnosed infected. We show that those two are approximately the same in exponential models and across most models currently used in the study of epidemics, independently of the model parameters. As an application, we compute an estimate of the effective number of infected by the SARS-CoV-2 virus in various countries.

Development and performance evaluation of a rapid in-house ELISA for retrospective serosurveillance of SARS-CoV-2

BACKGROUND

In the ongoing pandemic situation of COVID-19, serological tests can complement the molecular diagnostic methods, and can be one of the important tools of sero-surveillance and vaccine evaluation.

AIM

To develop and evaluate a rapid SARS-CoV-2 specific ELISA for detection of anti-SARS-CoV2 IgG from patients' biological samples.

METHODS

In order to develop this ELISA, three panels of samples (n = 184) have been used: panel 1 (n = 19) and panel 2 (n = 60) were collected from RT-PCR positive patients within 14 and after 14 days of onset of clinical symptoms, respectively; whereas panel 3 consisted of negative samples (n = 105) collected either from healthy donors or pre-pandemic dengue patients. As a capturing agent full-length SARS-CoV2 specific recombinant nucleocapsid was immobilized. Commercial SARS-CoV2 IgG kit based on chemiluminescent assay was used for the selection of samples and optimization of the assay. The threshold cut-off point, inter-assay and intra-assay variations were determined.

RESULTS

The incubation/reaction time was set at a total of 30 minutes with the sensitivity of 84% (95% confidence interval, CI, 60.4%, 96.6%) and 98% (95% CI, 91.1%, 100.0%), for panel 1 and 2, respectively; with overall 94.9% sensitivity (95% CI 87.5%, 98.6%). Moreover, the clinical specificity was 97.1% (95% CI, 91.9%, 99.4%) with no cross reaction with dengue samples. The overall positive and negative predictive values are 96.2% (95% CI 89.2%, 99.2%) and 96.2% (95% CI, 90.6% 99.0%), respectively. In-house ELISA demonstrated 100% positive and negative percent agreement with Elecsys Anti-SARS-CoV-2, with Cohen's kappa value of 1.00 (very strong agreement), while comparing 13 positive and 17 negative confirmed cases.

CONCLUSION

The assay is rapid and can be applied as one of the early and retrospective sero-monitoring tools in all over the affected areas.

The impact of novel coronavirus (2019-nCoV) pandemic movement control order (MCO) on dengue cases in Peninsular Malaysia

This study has highlighted the trend of recently-reported dengue cases after the implementation of the Movement Control Orders (MCOs) caused due to COVID-19 pandemic in Malaysia. The researchers used the dengue surveillance data published by the Malaysian Ministry of Health during the 3 phases of MCO (which ranged between 17th March 2020 and 28^th April 2020) was used for determining the cumulative number of dengue patients. Thereafter, the dengue cases were mapped using the Geographical Information System (GIS). The results indicated that during the 42 days of MCO in Peninsular Malaysia, 11,242 total cases of dengue were reported. The daily trend of the dengue cases showed a decrease from 7268 cases that occurred before the MCOs to 4662 dengue cases that occurred during the initial 14 days of the COVID-19 pandemic (i.e., MCO I), to 3075 cases occurring during the MCO II and 3505 dengue cases noted during MCO III. The central peninsular region showed a maximal decrease in new dengue cases (52.62%), followed by the northern peninsular region (1.89%); eastern coastal region (1.25%) and the southern peninsular region (1.14%) during the initial MCO implementation. However, an increase in the new dengue cases was noted during the MCO III period, wherein all states showed an increase in the new dengue cases as compared during MCO II. The decrease in the pattern was not solely based on the MCO, hence, further investigation is necessary after considering different influencing factors. These results have important implication for future large-scale risk assessment, planning and hazard mitigation on dengue management.

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Dengue has been described as a “silent killer” amidst the COVID-19 pandemic.

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The MCOs implemented by the Malaysian government to break the COVID-19 infection chain have positively affected the onset of new dengue cases.

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The highest reduction of new dengue cases were reported in the central peninsular region (52.62%), followed by the northern peninsular region (1.89%), eastern coastal region (1.25%) and the southern peninsular region (1.14%).

•

New dengue cases increased during the MCO3 period, with the increase of reported dengue cases in all states in Peninsular Malaysia.

More Is Not Enough: A Deeper Understanding of the COVID-19 Impacts on Healthcare, Energy and Environment Is Crucial

The coronavirus disease 2019 (COVID-19) pandemic has magnified the insufficient readiness of humans in dealing with such an unexpected occurrence. During the pandemic, sustainable development goals have been hindered severely. Various observations and lessons have been highlighted to emphasise local impacts on a single region or single sector, whilst the holistic and coupling impacts are rarely investigated. This study overviews the structural changes and spatial heterogeneities of changes in healthcare, energy and environment, and offers perspectives for the in-depth understanding of the COVID-19 impacts on the three sectors, in particular the cross-sections of them. Practical observations are summarised through the broad overview. A novel concept of the healthcare-energy-environment nexus under climate change constraints is proposed and discussed, to illustrate the relationships amongst the three sectors and further analyse the dynamics of the attention to healthcare, energy and environment in view of decision-makers. The society is still on the way to understanding the impacts of the whole episode of COVID-19 on healthcare, energy, environment and beyond. The raised nexus thinking could contribute to understanding the complicated COVID-19 impacts and guiding sustainable future planning.

Nucleoprotein-based ELISA for detection of SARS-COV-2 IgG antibodies: Could an old assay be suitable for serodiagnosis of the new coronavirus?

Objectives

We evaluated the performance of a nucleoprotein-based enzyme-linked immunosorbent assay (ELISA) for detection of IgG antibodies to SARS-CoV-2.

Methods

The ELISA was based on serum IgG reactivity to a 46-kDa protein derived from the recombinant SARS-CoV2 nucleoprotein. Assay sensitivity was assessed using serum samples from 134 COVID-19 confirmed cases obtained > 15 days after symptom onset. Specificity was determined by testing sera from 94 healthy controls. Cross-reactivity was evaluated with sera from 96 individuals with previous dengue or zika virus-confirmed infections, with 44 sera from individuals with confirmed infections to other respiratory viruses or with bacterial and fungal infections that cause pneumonia and with 40 sera negative for SARS-CoV-2 nucleoprotein by commercial ELISA kits.

Results

The majority of subjects were male and ≥ 60 years old. Assay sensitivity was 90.3 % (95 % confidence interval 84.1 %–94.2 %) and specificity was 97.9 % (92.6 %–99.4 %). There was no cross-reactivity with sera from individuals diagnosed with dengue, zika virus, influenza virus, rhinovirus, adenovirus, respiratory syncytial virus, seasonal coronavirus, Mycobacterium tuberculosis, Staphylococcus (S. aureus and coagulase-negative), Streptococcus pneumoniae, Klebsiella pneumoniae and the fungus Aspergillus fumigatus. The level of concordance of our test with results from commercial ELISA kits was 100 %.

Conclusion

The nucleoprotein-based ELISA was specific for detection of IgG anti-nucleoprotein antibodies to SARS-CoV-2. It utilizes a frequently employed low expense assay protocol and is easier to perform than other currently available commercial SARS-CoV2 antibody detection tests.

Contact System Activation in Plasma from Dengue Patients Might Harness Endothelial Virus Replication through the Signaling of Bradykinin Receptors

Since exacerbated inflammation and microvascular leakage are hallmarks of dengue virus (DENV) infection, here we interrogated whether systemic activation of the contact/kallikrein-kinin system (KKS) might hamper endothelial function. In vitro assays showed that dextran sulfate, a potent contact activator, failed to generate appreciable levels of activated plasma kallikrein (PKa) in the large majority of samples from a dengue cohort (n = 70), irrespective of severity of clinical symptoms. Impaired formation of PKa in dengue-plasmas correlated with the presence of cleaved Factor XII and high molecular weight kininogen (HK), suggesting that the prothrombogenic contact system is frequently triggered during the course of infection. Using two pathogenic arboviruses, DENV or Zika virus (ZIKV), we then asked whether exogenous BK could influence the outcome of infection of human brain microvascular endothelial cells (HBMECs). Unlike the unresponsive phenotype of Zika-infected HBMECs, we found that BK, acting via B2R, vigorously stimulated DENV-2 replication by reverting nitric oxide-driven apoptosis of endothelial cells. Using the mouse model of cerebral dengue infection, we next demonstrated that B2R targeting by icatibant decreased viral load in brain tissues. In summary, our study suggests that contact/KKS activation followed by BK-induced enhancement of DENV replication in the endothelium may underlie microvascular pathology in dengue.

COVID-19: What Should the General Practitioner Know?

BACKGROUND

SARS-CoV-2 infection is currently the most significant public health challenge. Its presentation ranges from mild to severe respiratory failure and septic shock. Rapid transmission of the virus is dangerous with a high possibility of life-threatening complications. Lack of treatment standards for SARS-CoV-2 is responsible for the current dilemma in clinical medicine.

METHODS

An electronic literature search was done using PubMed to gather information on the pathogenesis, transmission of infection, clinical symptoms, diagnosis, and therapeutic options for COVID-19. Search items included "SARS-CoV-2", "COVID-19" and "coronavirus infection".

RESULTS

In light of the current global crisis caused by SARS-CoV-2, the exchange of information within the scientific community should be quick and extremely transparent. Thus, this review presents the available information necessary for a general practitioner. Such presentation of data should allow the reader quick access to basic and crucial information related to epidemiology, viral transmission, clinical symptoms, diagnostics, treatment, and complications that may occur in the course of COVID-19.

CONCLUSION

Rapidly increasing amounts of information about the diagnosis and treatment of patients with SARS-CoV-2 allow a better understanding of the etiology and course of the infection. In the current epidemiological situation, readily accessible information helps minimize the time to acquire knowledge and focus on prevention methods, diagnostic and treatment options. Thus, this review highlights key issues related to SARS-CoV-2 infection and contains the most useful data for daily medical practice.

Covert cases of Severe Acute Respiratory Syndrome Coronavirus 2: An obscure but present danger in regions endemic for Dengue and Chikungunya viruses

BACKGROUND

The impact of SARS-CoV-2 in regions endemic for both Dengue and Chikungunya is still not fully understood. Considering that symptoms/clinical features displayed during Dengue, Chikungunya and SARS-CoV-2 acute infections are similar, undiagnosed cases of SARS-CoV-2 in co-endemic areas may be more prevalent than expected. This study was conducted to assess the prevalence of covert cases of SARS-CoV-2 among samples from patients with clinical symptoms compatible with either Dengue or Chikungunya viral infection in the state of Espírito Santo, Brazil.

METHODS

Presence of immunoglobulin G (IgG) antibody specific to SARS-CoV-2 nucleoprotein was detected using a chemiluminescent microparticle immunoassay in samples from 7,370 patients, without previous history of COVID-19 diagnosis, suspected of having either Dengue (n = 1,700) or Chikungunya (n = 7,349) from December 1st, 2019 to June 30th, 2020.

FINDINGS

Covert cases of SARS-CoV-2 were detected in 210 (2.85%) out of the 7,370 serum samples tested. The earliest undiagnosed missed case of COVID-19 dated back to a sample collected on December 18, 2019, also positive for Dengue Virus. Cross-reactivity with either Dengue virus or other common coronaviruses were not observed.

INTERPRETATION

Our findings demonstrate that concomitant Dengue or Chikungunya outbreaks may difficult the diagnosis of SARS-CoV-2 infections. To our knowledge, this is the first study to demonstrate, with a robust sample size (n = 7,370) and using highly specific and sensitive chemiluminescent microparticle immunoassay method, that covert SARS-CoV-2 infections are more frequent than previously expected in Dengue and Chikungunya hyperendemic regions. Moreover, our results suggest that SAR-CoV-2 cases were occurring prior to February, 2020, and that these undiagnosed missed cases may have contributed to the fast expansion of SARS-CoV-2 outbreak in Brazil. Data presented here demonstrate that in arboviral endemic regions, SARS-CoV-2 infection must be always considered, regardless of the existence of a previous positive diagnosis for Dengue or Chikungunya.

What Is the Impact of Lockdowns on Dengue?

PURPOSE OF REVIEW

Societal lockdowns in response to the COVID-19 pandemic have led to unprecedented disruption to daily life across the globe. A collateral effect of these lockdowns may be a change to transmission dynamics of a wide range of infectious diseases that are all highly dependent on rates of contact between humans. With timing, duration and intensity of lockdowns varying country-to-country, the wave of lockdowns in 2020 present a unique opportunity to observe how changes in human contact rates, disease control and surveillance affect dengue virus transmission in a global natural experiment. We explore the theoretical basis for the impact of lockdowns on dengue transmission and surveillance then summarise the current evidence base from country reports.

RECENT FINDINGS

We find considerable variation in the intensity of dengue epidemics reported so far in 2020 with some countries experiencing historic low levels of transmission while others are seeing record outbreaks. Despite many studies warning of the risks of lockdown for dengue transmission, few empirically quantify the impact and issues such as the specific timing of the lockdowns and multi-annual cycles of dengue are not accounted for. In the few studies where such issues have been accounted for, the impact of lockdowns on dengue appears to be limited.

SUMMARY

Studying the impact of lockdowns on dengue transmission is important both in how we deal with the immediate COVID-19 and dengue crisis, but also over the coming years in the post-pandemic recovery period. It is clear lockdowns have had very different impacts in different settings. Further analyses might ultimately allow this unique natural experiment to provide insights into how to better control dengue that will ultimately lead to better long-term control.

Immunity after COVID-19: Protection or sensitization?

Motivated by historical and present clinical observations, we discuss the possible unfavorable evolution of the immunity (similar to documented antibody-dependent enhancement scenarios) after a first infection with COVID-19. More precisely we ask the question of how the epidemic outcomes are affected if the initial infection does not provide immunity but rather sensitization to future challenges. We first provide background comparison with the 2003 SARS epidemic. Then we use a compartmental epidemic model structured by immunity level that we fit to available data; using several scenarios of the fragilization dynamics, we derive quantitative insights into the additional expected numbers of severe cases and deaths.

COVID-19 in Singapore - a case series from primary care

As the COVID-19 pandemic worsens, early case detection is vital to limiting community spread. We describe our experiences with four COVID-19 cases at the polyclinics in January and February 2020. This retrospective case series highlights the challenges primary care clinicians face in the early identification of suspect cases based on clinical criteria only. To improve case detection, clinicians can sharpen their clinical acumen by keeping abreast with the latest COVID-19 developments and by maintaining a high state of vigilance.

Characteristics of Patients Co-infected with Severe Acute Respiratory Syndrome Coronavirus 2 and Dengue Virus, Buenos Aires, Argentina, March-June 2020

An epidemic of dengue virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) co-infections occurred in Argentina during 2020. We describe the clinical characteristics and outcomes in a cohort of patients hospitalized because of co-infection. We retrospectively identified 13 patients from different hospitals in Buenos Aires who had confirmed infection with SARS-CoV-2 and dengue virus and obtained clinical and laboratory data from clinical records. All patients had febrile disease when hospitalized. Headache was a common symptom. A total of 8 patients had respiratory symptoms, 5 had pneumonia, and 3 had rash. Nearly all patients had lymphopenia when hospitalized. No patients were admitted to an intensive care unit or died during follow up. Co-infection with SARS-CoV-2 and dengue virus can occur in patients living in areas in which both viruses are epidemic. The outcome of these patients did not seem to be worse than those having either SARS-CoV-2 or dengue infection alone.

Approach to acute febrile illness during the COVID-19 pandemic

Coronavirus disease 2019 (COVID-19) is a febrile respiratory illness that has spread rampantly across the globe and has emerged as one of the biggest pandemics of all time. Besides the direct effects of COVID-19 on mortality, collateral impacts on diagnosis and management of acute febrile illnesses (AFI) is a matter of great concern. The overlap in presentation, shunting of available resources and infection control precautions in patients with suspected COVID-19 result in a significant delay in diagnoses and management of AFI. This review highlights the challenges in the management of acute febrile illness during COVID pandemic and possible solutions for the same.

Computational modelling supports that dengue virus envelope antibodies can bind to SARS-CoV-2 receptor binding sites: Is pre-exposure to dengue virus protective against COVID-19 severity?

The world is going through the scourge of the COVID-19 pandemic since January 2020. However, the pandemic appears to be less severe in highly dengue endemic countries. In this connection, several studies reported that sero-diagnostic tests for dengue virus (DV) yielded considerable false-positive results for SARS-CoV-2 and vice versa in dengue endemic regions, thereby indicating towards potential cross-reactivity between these two viruses. We anticipated that SARS-CoV-2 and DV might share antigenic similarity and performed computational docking studies to test this hypothesis. Our results predicted with high confidence that human DV antibodies can indeed, bind to RBD of SARS-CoV-2 Spike protein. Some of these interactions can also potentially intercept human ACE2 receptor binding to RBM. Dengue serum samples predating the COVID-19, had been found to cross-react with SARS-CoV-2 Spike and this provides direct experimental validation of our predictions. Our analysis also showed that m396 and 80R antibodies (against SARS-CoV-1) did not dock with RBM of SARS-CoV-2, a fact already proven experimentally. This confirmed reliability and robustness of our approach. So, it is highly probable that immunological memory/antibodies to DV in endemic countries may reduce the severity and spread of COVID-19. It is not known whether SARS-CoV-2 antibodies will hinder DV infections by binding to DV particles and reduce dengue incidences in the future or, augment DV infection and severity by deploying antibody-dependent enhancement.

Impact of COVID-19 in patients with concurrent co-infections: A systematic review and meta-analyses

The burden and impact of secondary superadded infections in critically ill coronavirus disease 2019 (COVID-19) patients is widely acknowledged. However, there is a dearth of information regarding the impact of COVID-19 in patients with tuberculosis, HIV, chronic hepatitis, and other concurrent infections. This review was conducted to evaluate the consequence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in patients with concurrent co-infections based on the publications reported to date. An extensive comprehensive screening was conducted using electronic databases up to 3rd September 2020 after obtaining registration with PROSPERO (CRD420202064800). The observational studies or interventional studies in English, evaluating the impact of SARS-CoV-2 in patients with concurrent infections are included for the meta-analyses. Our search retrieved 20 studies, with a total of 205,702 patients. Patients with tuberculosis (RR = 2.10; 95% CI, 1.75-2.51; I²  = 0%), influenza (RR = 2.04; 95% CI, 0.15-28.25, I²  = 99%) have an increased risk of mortality during a co-infection with SARS-CoV-2. No significant impact is found in people living with HIV (RR = 0.99; 95% CI, 0.82-1.19; I²  = 30%), Chronic hepatitis (RR = 1.15; 95% CI, 0.73-1.81; I²  = 10%). Several countries (Brazil, Paraguay, Argentina, Peru, Colombia, and Singapore) are on the verge of a dengue co epidemic (cumulative 878,496 and 5,028,380 cases of dengue and COVID-19 respectively). The impact of COVID-19 in patients of concurrent infections with either tuberculosis or influenza is detrimental. The clinical outcomes of COVID-19 in HIV or chronic hepatitis patients are comparable to COVID-19 patients without these concurrent infections.

COVID-19 with dengue shock syndrome in a child: coinfection or cross-reactivity?

COVID-19, caused by SARS-CoV-2, has spread globally. Coinfection with other endemic viruses is likely to complicate the clinical presentation and outcome. Information on clinical manifestations and management strategies on COVID-19 coinfection with endemic diseases in children is yet to evolve. The risk of dengue infection exists in 129 countries and it is endemic in more than 100 countries. The SARS-CoV-2 pandemic might overlap with the dengue epidemics in tropical countries. We report the first paediatric case to the best of our knowledge of COVID-19 encephalitis with dengue shock syndrome. This clinical syndrome could be attributed to serological cross-reactivity, incidental coinfection or perhaps a warning for dengue-endemic regions to face the unique challenge of differentiating and managing two disease entities together. Enhanced understanding of potential COVID-19 and dengue coinfection warrants immediate attention of researchers and international health policy makers.

Simultaneous Circulation of DENV, CHIKV, ZIKV and SARS-CoV-2 in Brazil: an Inconvenient Truth

The emergence of SARS-CoV-2 has prompted the mobilization of a network of public health laboratories to diagnose COVID-19 patients, trace contacts and identify hot-spot areas for active community transmission at the expense of arbovirus diagnosis and control practices. In this article, we discuss the unprecedented challenges faced by the Brazilian public health system in dealing with the incursion of SARS-CoV-2 in the midst of ongoing triple arboviral epidemics caused by dengue, chikungunya, and Zika virus. Finally, we highlight the importance of the introduction of one health approach as an effective inter-disciplinary response and management to mitigate the catastrophic effect caused by these pathogens.

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SARS-CoV-2 emerged in Brazil in the midst of ongoing triple arboviral epidemics caused by DENV, CHIKV and ZIKV.

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The emergence of SARS-CoV-2 has prompted the mobilization of public health laboratories and officials at the expense of arbovirus diagnosis and control practices.

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The simultaneous circulation of SARS-CoV-2 and arboviruses in Brazil requires the integration of disease control measures and effective surveillance programs.

Case Report: Dengue and COVID-19 Coinfection in Thailand

We report a 50-year-old Thai woman with recent travel to Denmark who presented with acute high-grade fever, vomiting, and myalgia for 1 day. Initial laboratory results revealed leukopenia, elevated aspartate transaminase, and elevated alanine transaminase. Chest radiograph showed no pulmonary infiltration. Reverse transcriptase–PCR (RT-PCR) of the nasopharyngeal swab detected SARS-CoV-2, and RT-PCR of the blood detected dengue virus serotype 2. COVID-19 with dengue fever co-infection was diagnosed. Her symptoms were improved with supportive treatment. Integration of clinical manifestations, history of exposure, laboratory profiles, and dynamic of disease progression assisted the physicians in precise diagnosis. Co-circulating and nonspecific presentations of dengue infection and COVID-19 challenge the healthcare system in tropical countries. To solve this threat, multi-sector strategies are required, including public health policy, development of accurate point-of-care testing, and proper prevention for both diseases.

Experience of a Tertiary Hospital in Singapore with Management of a Dual Outbreak of COVID-19 and Dengue

During the COVID-19 pandemic, distinguishing dengue from cases of COVID-19 in endemic areas can be difficult. In a tertiary hospital contending with COVID-19 during a dengue epidemic, a triage strategy of routine COVID-19 testing for febrile patients with viral prodromes was used. All febrile patients with viral prodromes and no epidemiologic risk for COVID-19 were first admitted to a designated ward for COVID-19 testing, where enhanced personal protective equipment was used by healthcare workers until COVID-19 was ruled out. From January to May 2020, 11,086 admissions were screened for COVID-19; 868 cases of COVID-19 were diagnosed in our institution, along with 380 cases of dengue. Only 8.5% (943/11,086) of suspected COVID-19 cases were concurrently tested for dengue serology due to a compatible overlapping clinical syndrome, and dengue was established as an alternative diagnosis in 2% (207/10,218) of suspected COVID-19 cases that tested negative. There were eight COVID-19 cases with likely false-positive dengue serology and one probable COVID-19/dengue coinfection. From April to May 2020, 251 admissions presenting as viral prodromes with no respiratory symptoms were screened; of those, 15 cases had COVID-19, and 2/15 had false-positive dengue IgM. Epidemiology investigations showed no healthcare-associated transmission. In a dengue epidemic season coinciding with a COVID-19 pandemic, dengue was established as an alternative diagnosis in a minority of COVID-19 suspects, likely due to early availability of basic diagnostics. Routine screening of patients with viral prodromes during a dual outbreak of COVID-19 and dengue enabled containment of COVID-19 cases masquerading as dengue with false-positive IgM.

A Patient With Dengue Fever and COVID-19: Coinfection or Not?

Co-epidemics can create a burden on healthcare systems in the affected areas. The world, at present, is facing the pandemic of coronavirus disease. Nonetheless, many areas worldwide suffer from endemics that are not of less danger than the current pandemic. We presented a case of a patient diagnosed with dengue fever and was also found to have coronavirus through nasal swab, but immunoglobulin M and G were undetectable. Our case brings to notice the alarming probability of two co-epidemics happening simultaneously. However, through the presented case, our theory is that the dengue virus may cause a false-positive detection of severe acute respiratory syndrome coronavirus 2.

Evaluation of an Electrochemiluminescent SARS-CoV-2 Antibody Assay

BACKGROUND

Little is known about the performance of the Roche novel severe acute respiratory syndrome coronavirus 2 antibody (anti-SARS-CoV-2) assay. We provide an extensive evaluation of this fully automated assay on Cobas e801/e602 immunoassay analyzers.

METHODS

We assessed the linearity, precision, and throughput of the Roche anti-SARS-CoV-2 assay. Sensitivity was calculated from 349 SARS-CoV-2 polymerase chain reaction (PCR) positive samples; specificity was determined from 715 coronavirus disease 2019 (COVID-19)-naive samples. We examined cross-reactivity against other antibody positive samples [syphilis, rheumatoid factor (RF), antinuclear antibody (ANA), double-stranded DNA (ds-DNA), influenza, dengue, hepatitis B (HBV), hepatitis C (HCV)] and the anti-SARS-CoV-2 kinetics.

RESULTS

The assay cut-off index (COI) was linear up to 90.8. The interassay precision was 2.9% for a negative control (COI = 0.1) and 5.1% for a positive control (COI = 3.0). Assay time is 18 min and results are available 1 min later; throughput for 300 samples was 76 min. Only 1 case positive for HBsAg tested falsely positive; specificity was 99.9%. The assay has a sensitivity of 97.1% 14 days after PCR positivity (POS) and 100% at ≥21 days POS; 48.2% of cases had anti-SARS-CoV-2 within 6 days POS. In 11 patients in whom serum was available prior to a positive antibody signal (COI ≥1.0) the interval between the last negative and first positive COI (time to "seroconversion") on average is 3 days (range 1-6 days) and 4 more days (range 1-7) for the anti-SARS-CoV-2 to plateau.

CONCLUSION

The Roche anti-SARS-CoV-2 assay shows excellent performance with minimal cross-reactivity from other viral and confounding antibodies. Antibody development and seroconversion appears quite early.

Nurse infected with Covid-19 from a provisional dengue patient

We report a 35-year-old female nurse who possibly received the SARS-CoV-2 virus during the blood sampling of a 35-year-old male patient initially suspected as a dengue infection. The patient had mild thrombocytopenia and positive dengue IgG and IgM whereas the clinicians were not aware of the possibility of false-positive dengue serology revealed in the published case report from Singapore. The nurse put on a pair of gloves but did not wear a mask during the only encounter with this patient. This nosocomial transmission raised a safety concern among healthcare professionals in an area with a relatively low Covid-19 prevalence, especially when the clinical and laboratory characteristics could be confused with other viral infections.

Atypical presentation of COVID-19; an observational retrospective study

BACKGROUND

COVID-19 infection may present with atypical signs and symptoms and false negative polymerase chain reaction (PCR) tests predisposing healthy people and health care workers to infection. The aim of the current study is to evaluate the features of atypical presentations in COVID-19 infection in a referral center in Tehran, Iran.

METHODS

Hospital database of inpatients admitted to Loghman Hakim hospital between February 20th and May 11th, 2020 was reviewed and all patients with final diagnosis of COVID-19 infection were evaluated for their presenting symptoms. Patients with chief complaints of "fever", "dyspnea", and/or "cough" as typical presentations of COVID-19 were excluded and those with other clinical presentations were included.

RESULTS

Nineteen patients were included with a mean age of 51 ± 19 years, of whom, 17 were males (89%). Median [IQR] Glasgow coma scale (GCS) was 14 [13, 15]. Almost 10 had referred with chief complaint of methanol poisoning and overdose on substances of abuse. Only 8 cases (42%) had positive COVID-19 test. Nine (47%) needed invasive mechanical ventilation, of whom, two had positive COVID-19 test results (p = ns). Eight patients (42%) died with three of them having positive PCRs.

CONCLUSIONS

In patients referring to emergency departments with chief complaint of poisoning (especially poisonings that can result in dyspnea including substances of abuse and toxic alcohols), gastrointestinal, and constitutional respiratory symptoms, attention should be given not to miss possible cases of COVID-19.