Validation of a commercially available SARS-CoV-2 serological immunoassay.

OBJECTIVES: To validate the diagnostic accuracy of a Euroimmun SARS-CoV-2 IgG and IgA immunoassay for COVID-19. METHODS: In this unmatched (1:2) case-control validation study, we used sera of 181 laboratory-confirmed SARS-CoV-2 cases and 326 controls collected before SARS-CoV-2 emergence. Diagnostic accuracy of the immunoassay was assessed against a whole spike protein-based recombinant immunofluorescence assay (rIFA) by receiver operating characteristic (ROC) analyses. Discrepant cases between ELISA and rIFA were further tested by pseudo-neutralization assay. RESULTS: COVID-19 patients were more likely to be male and older than controls, and 50.3% were hospitalized. ROC curve analyses indicated that IgG and IgA had high diagnostic accuracies with AUCs of 0.990 (95% Confidence Interval [95%CI]: 0.983-0.996) and 0.978 (95%CI: 0.967-0.989), respectively. IgG assays outperformed IgA assays (p=0.01). Taking an assessed 15% inter-assay imprecision into account, an optimized IgG ratio cut-off > 2.5 displayed a 100% specificity (95%CI: 99-100) and a 100% positive predictive value (95%CI: 96-100). A 0.8 cut-off displayed a 94% sensitivity (95%CI: 88-97) and a 97% negative predictive value (95%CI: 95-99). Substituting the upper threshold for the manufacturer's, improved assay performance, leaving 8.9% of IgG ratios indeterminate between 0.8-2.5. CONCLUSIONS: The Euroimmun assay displays a nearly optimal diagnostic accuracy using IgG against SARS-CoV-2 in patient samples, with no obvious gains from IgA serology. The optimized cut-offs are fit for rule-in and rule-out purposes, allowing determination of whether individuals in our study population have been exposed to SARS-CoV-2 or not. IgG serology should however not be considered as a surrogate of protection at this stage.

Emerging souvenirs-clinical presentation of the returning traveller with imported arbovirus infections in Europe.

BACKGROUND: Arboviruses are an emerging group of viruses that are causing increasing health concerns globally, including in Europe. Clinical presentation usually consists of a nonspecific febrile illness that may be accompanied by rash, arthralgia and arthritis, with or without neurological or haemorrhagic syndromes. The range of differential diagnoses of other infectious and noninfectious aetiologies is broad, presenting a challenge for physicians. While knowledge of the geographical distribution of pathogens and the current epidemiological situation, incubation periods, exposure risk factors and vaccination history can help guide the diagnostic approach, the nonspecific and variable clinical presentation can delay final diagnosis. AIMS AND SOURCES: This narrative review aims to summarize the main clinical and laboratory-based findings of the three most common imported arboviruses in Europe. Evidence is extracted from published literature and clinical expertise of European arbovirus experts. CONTENT: We present three cases that highlight similarities and differences between some of the most common travel-related arboviruses imported to Europe. These include a patient with chikungunya virus infection presenting in Greece, a case of dengue fever in Turkey and a travel-related case of Zika virus infection in Romania. IMPLICATIONS: Early diagnosis of travel-imported cases is important to reduce the risk of localized outbreaks of tropical arboviruses such as dengue and chikungunya and the risk of local transmission from body fluids or vertical transmission. Given the global relevance of arboviruses and the continuous risk of (re)emerging arbovirus events, clinicians should be aware of the clinical syndromes of arbovirus fevers and the potential pitfalls in diagnosis.

Laboratory preparedness and response with a focus on arboviruses in Europe.

BACKGROUND: The global health burden of arboviruses is continuously rising, which results in increasing pressure on local and (inter)national laboratory infrastructures. Timely and accurate diagnosis of cases is one of the main pillars for public health and clinical responses to an arbovirus emergence. AIMS AND SOURCES: This narrative review aims to summarize recent advances and to identify needs in laboratory preparedness and response activities, with a focus on viruses transmitted by arthropods in Europe. The review is based on evidence extracted from PubMed searches, Public Health and clinical laboratory experiences from the authors and the authors' opinions substantiated by peer-reviewed scientific literature. CONTENT: We illustrate the importance of inter-epidemic laboratory preparedness activities to ensure adequate Public Health and clinical responses. We describe the status of arbovirus endemicity and emergence in Europe thereby highlighting the need for preparedness for these viruses. We discuss the components and pitfalls of an adequate laboratory preparedness and response and the broader context of the current landscape of international research, clinical and laboratory preparedness networks. The complexity of arbovirus laboratory preparedness and response is described. IMPLICATIONS: Outbreak preparedness plans need to look beyond national reference laboratories, to include first-line responding onsite hospital laboratories and plans for strengthening of such local capacity and capability as required depending on the nature of the outbreak. In particular, the diagnosis of arbovirus infections is complicated by the existence of geographic overlap of circulation of numerous arboviruses, the overlap in clinical manifestation between many arboviruses and other aetiologies and the existence of cross-reactivity between related arboviruses in serology testing. Inter-epidemic preparedness activities need strong national and international networks addressing these issues. However, the current mushrooming of European preparedness networks requires governance to bring the European preparedness and response to a next level.

Preparing clinicians for (re-)emerging arbovirus infectious diseases in Europe.

BACKGROUND: Arthropod-borne virus (Arbovirus) infections are considered an emerging threat for Europe, with an increase in cases in recent decades. The increase in global travel and trade has contributed to the introduction of vectors and viruses into new geographical areas. Tropical arboviruses such as dengue and chikungunya have re-emerged causing local, sporadic outbreaks ignited by travel-imported cases. The recent Zika virus outbreak in the Americas highlighted a need to strengthen preparedness for (re-)emerging arbovirus infections globally. AIMS: To strengthen preparedness for the early identification of (re-)emerging arbovirus outbreaks in Europe and highlight areas for research. SOURCES: An evidence review of published and grey literature together with consultations with European arbovirus experts. CONTENT: This paper presents an overview of endemic and travel-imported arboviruses of clinical significance in Europe. The overview includes syndromic presentation, risk factors for infection and risk of transmission as well as an update on treatments and vaccinations and surveillance notifications and reporting. The paper also presents predictive modelled risks of further geographical expansion of vectors and viruses. IMPLICATIONS: There are a range of arboviruses of clinical significance to Europe. There has been an increase in notifications of endemic and travel-imported arbovirus cases in recent years and an increased geographical range of vectors and viruses. The heterogeneity in surveillance reporting indicates a risk for the early identification of (re-)emerging outbreaks. The data presented show a need to strengthen preparedness for (re-)emerging arbovirus infections and a need for research into neglected arboviruses, risks of non-vector transmission and effective therapeutics and vaccinations.

Detection of a novel human coronavirus by real-time reverse-transcription polymerase chain reaction.

We present two real-time reverse-transcription polymerase chain reaction assays for a novel human coronavirus (CoV), targeting regions upstream of the E gene (upE) or within open reading frame (ORF)1b, respectively. Sensitivity for upE is 3.4 copies per reaction (95% confidence interval (CI): 2.5­6.9 copies) or 291 copies/mL of sample. No cross-reactivity was observed with coronaviruses OC43, NL63, 229E, SARS-CoV, nor with 92 clinical specimens containing common human respiratory viruses. We recommend using upE for screening and ORF1b for confirmation.

Atypical severe Puumala hantavirus infection and virus sequence analysis of the patient and regional reservoir host.

Nephropathia epidemica (NE) caused by Puumala hantavirus (PUUV) is a mild variant of haemorrhagic fever with renal syndrome, which is endemic in Germany. We describe the case of a 67-year-old man initially presenting with acute bilateral angle-closure glaucoma, an atypical clinical presentation of PUUV infection. Subsequently, the patient developed a severe course of disease additionally complicated by profound hepatitis and interstitial nephritis, both phenomena which are rarely described in association with hantavirus infection. Serologic diagnosis was complicated by delayed antibody production until the 10th day of illness; however, PUUV RNA was detectable early in disease. To further analyse this unusual case, sequencing of the PUUV S segment was performed from the patient and regional reservoir host which showed a close relation.