Performance Analysis of Serodiagnostic Tests to Characterize the Incline and Decline of the Individual Humoral Immune Response in COVID-19 Patients: Impact on Diagnostic Management.

Serodiagnostic tests for antibody detection to estimate the immunoprotective status regarding SARS-CoV-2 support diagnostic management. This study aimed to investigate the performance of serological assays for COVID-19 and elaborate on test-specific characteristics. Sequential samples ( = 636) of four panels (acute COVID-19, convalescent COVID-19 (partly vaccinated post-infection), pre-pandemic, and cross-reactive) were tested for IgG by indirect immunofluorescence test (IIFT) and EUROIMMUN EUROLINE Anti-SARS-CoV-2 Profile (IgG).

Dried blood spot eluates are suitable for testing of SARS-CoV-2 IgG antibodies targeting Spike protein 1 and Nucleocapsid protein.

Dried blood spots (DBS) provide easy handling and are thus a beneficial tool for data collection, e.g. for epidemiological studies.

Humoral Immune Response to CoronaVac in Turkish Adults.

While most approved vaccines are based on the viral spike protein or its immunogenic regions, inactivated whole-virion vaccines (e.g., CoronaVac) contain additional antigens that may enhance protection.

Evaluation of Nucleoprotein-Based Enzyme-Linked Immunosorbent Assay for Serodiagnosis of Acute Crimean-Congo Hemorrhagic Fever Virus Infections in a Turkish Population.

Crimean-Congo hemorrhagic fever virus (CCHFV) causes a highly contagious tick-borne disease with high case-fatality rates in humans. It is circulating not only in many Asian and African countries, but also spreading to and within Europe. To cope better with future outbreaks of Crimean-Congo hemorrhagic fever (CCHF), the WHO has prioritized the need for the development and validation of CCHF diagnostics, including serological assays.

Frequent intrathecal production of antibodies to the viral capsid antigen of Epstein-Barr virus in patients with central nervous system post-transplant lymphoproliferative disorder.

Primary central nervous system post-transplant lymphoproliferative disorder (PCNS-PTLD) is strongly associated with Epstein-Barr virus (EBV). We analysed intrathecal production of EBV viral capsid antigen (VCA) immunoglobulin (Ig)G and IgA and Epstein-Barr nuclear antigen-1 (EBNA-1) IgG in nine patients with PNCS-PTLD and 20 patients with non-inflammatory neurological diseases (NINDs). Intrathecally produced VCA-IgG was detected in 7/9 (78%), VCA-IgA in 6/9 (67%) and EBNA-1-IgG in 2/9 (22%) patients with PCNS-PTLD, but not in NINDs.

B-cell responses to vaccination with BNT162b2 and mRNA-1273 6 months after second dose.

Objectives: To examine the state of B-cell immunity 6 months after the second vaccination against SARS-CoV-2 in comparison to the state observed 2 weeks after vaccination.

Methods: Sera of 439 participants, whose immune responses to two doses of an mRNA-based vaccine (BNT162b2 or mRNA-1273) were previously characterized, was examined for anti-S1 IgG and IgA, anti-NCP IgG and neutralizing antibodies (nAb), and antinuclear antibodies (ANA).

Results: Levels of all examined markers decreased significantly from 2 weeks to 6 months after second vaccination (anti-S1 IgG: 3744 ± 2571.

Kinetics of the Antibody Response to Boostering With Three Different Vaccines Against SARS-CoV-2.

Background: Heterologous vaccinations against SARS-CoV-2 with ChAdOx1 nCoV-19 and a second dose of an mRNA-based vaccine have been shown to be more immunogenic than homologous ChAdOx1 nCoV-19. In the current study, we examined the kinetics of the antibody response to the second dose of three different vaccination regimens (homologous ChAdOx1 nCoV-19 vs. ChAdOx1 nCoV-19 + BNT162b2 or mRNA-1273) against SARS-CoV-2 in a longitudinal manner; whether there are differences in latency or amplitude of the early response and which markers are most suitable to detect these responses.

The temporal course of T- and B-cell responses to vaccination with BNT162b2 and mRNA-1273.

Objectives: To investigate the response of the immune system (and its influencing factors) to vaccination with BNT162b2 or mRNA-1273.

Methods: 531 vaccinees, recruited from healthcare professionals, donated samples before, in between, and after the administration of the two doses of the vaccine. T- and B-cell responses were examined via interferon-γ (IFN-γ) release assay, and antibodies against different epitopes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (S1 and NCP) were detected via ELISA and surrogate neutralization assay.

Correlation between a quantitative anti-SARS-CoV-2 IgG ELISA and neutralization activity.

In the current COVID-19 pandemic, a better understanding of the relationship between merely binding and functionally neutralizing antibodies is necessary to characterize protective antiviral immunity following infection or vaccination. This study analyzes the level of correlation between the novel quantitative EUROIMMUN Anti-SARS-CoV-2 QuantiVac ELISA (IgG) and a microneutralization assay. A panel of 123 plasma samples from a COVID-19 outbreak study population, preselected by semiquantitative anti-SARS-CoV-2 IgG testing, was used to assess the relationship between the novel quantitative ELISA (IgG) and a microneutralization assay.

Longitudinal detection of SARS-CoV-2-specific antibody responses with different serological methods.

Serological testing for anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies is used to detect ongoing or past SARS-CoV-2 infections. To study the kinetics of anti-SARS-CoV-2 antibodies and to assess the diagnostic performances of eight serological assays, we used 129 serum samples collected on known days post symptom onset (dpso) from 42 patients with polymerase chain reaction-confirmed coronavirus disease 2019 (COVID-19) and 54 serum samples from healthy blood donors, and children infected with seasonal coronaviruses. The sera were analyzed for the presence of immunoglobulin G (IgG), immunoglobulin M (IgM), and immunoglobulin A (IgA) antibodies using indirect immunofluorescence testing (IIFT) based on SARS-CoV-2-infected cells.

Evaluation of dried blood spots as alternative sampling material for serological detection of anti-SARS-CoV-2 antibodies using established ELISAs.

Objectives: During the current pandemic, antibody testing based on venous serum helps to determine whether the tested person has been previously infected with SARS-CoV-2. Alternatively, capillary blood can be taken via a finger prick (dried blood spots, DBS). In this study, paired DBS and venipuncture samples were tested using two serological assays to evaluate the usability of DBS for the detection of anti-SARS-CoV-2 antibodies.

Heavy Exposure of Children Aged 9-12 Years With Severe Acute Respiratory Syndrome Coronavirus 2 Did Not Lead to Infection.

The reason for the apparently lower infection rate of children with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) compared to adults is still unclear. Here, we report on 4 schoolchildren with heavy exposure to SARS-CoV-2 with no clinical signs of coronavirus disease 2019, repeated negative nasopharyngeal swabs for SARS-CoV-2 RNA, and no seroconversion.

Added value of IgA antibodies against Zika virus non-structural protein 1 in the diagnosis of acute Zika virus infections.

Zika virus (ZIKV) is a mosquito-borne flavivirus posing a public health threat due to its association with neurological complications in newborns and adults. In flavivirus-endemic areas, coming mosquito seasons will require the differentiation of primary versus secondary and acute versus past ZIKV/flavivirus infections. This is complicated by two major difficulties: [i] secondary infections often present with low or undetectable titres of specific IgM and with early-positive IgG, [ii] previous flavivirus infection(s) or vaccinations cause elevated cross-reactivities.

A Community Study of Antibodies among Individuals with Prior Lyme Disease in Endemic Areas.

The objective was to examine the prevalence of antibodies among symptomatic individuals with recent and past Lyme disease in endemic communities using standard assays and novel assays employing next-generation antigenic substrates. Single- and two-tiered algorithms included different anti- ELISAs and immunoblots. Antibody prevalence was examined in sera from 32 individuals with recent erythema migrans (EM), 335 individuals with persistent symptoms following treatment for Lyme disease (PTLS), and 41 community controls without a history of Lyme disease.

Reliable Serological Testing for the Diagnosis of Emerging Infectious Diseases.

Climate change, increased urbanization and international travel have facilitated the spread of mosquito vectors and the viral species they carry. Zika virus (ZIKV) is currently spreading in the Americas, while dengue virus (DENV) and chikungunya virus (CHIKV) have already become firmly established in most tropical and also many non-tropical regions. ZIKV, DENV and CHIKV overlap in their endemic areas and cause similar clinical symptoms, especially in the initial stages of infection.

Serodiagnosis of Zika virus (ZIKV) infections by a novel NS1-based ELISA devoid of cross-reactivity with dengue virus antibodies: a multicohort study of assay performance, 2015 to 2016.

Serological diagnosis of Zika virus (ZIKV) infections is challenging due to high cross-reactivity between flaviviruses. We evaluated the diagnostic performance of a novel anti-ZIKV ELISA based on recombinant ZIKV non-structural protein 1 (NS1). Assay sensitivity was examined using sera from 27 patients with reverse transcription (RT)-PCR-confirmed and 85 with suspected ZIKV infection.

Hepatitis E Virus Infection in Dromedaries, North and East Africa, United Arab Emirates, and Pakistan, 1983-2015.

A new hepatitis E virus (HEV-7) was recently found in dromedaries and 1 human from the United Arab Emirates. We screened 2,438 dromedary samples from Pakistan, the United Arab Emirates, and 4 African countries. HEV-7 is long established, diversified and geographically widespread.

Viral Shedding and Antibody Response in 37 Patients With Middle East Respiratory Syndrome Coronavirus Infection.

Background: The Middle East respiratory syndrome (MERS) coronavirus causes isolated cases and outbreaks of severe respiratory disease. Essential features of the natural history of disease are poorly understood.

Methods: We studied 37 adult patients infected with MERS coronavirus for viral load in the lower and upper respiratory tracts (LRT and URT, respectively), blood, stool, and urine.

Infectious Middle East Respiratory Syndrome Coronavirus Excretion and Serotype Variability Based on Live Virus Isolates from Patients in Saudi Arabia.

The newly emerged Middle East respiratory syndrome coronavirus (MERS-CoV) has infected at least 1,082 people, including 439 fatalities. So far, no empirical virus isolation study has been done to elucidate infectious virus secretion or serotype variability. Here, we used 51 respiratory samples from 32 patients with confirmed MERS-CoV infection for virus isolation in Vero B4 and Caco-2 cells.

CMV specific cytokine release assay in whole blood is optimized by combining synthetic CMV peptides and toll like receptor agonists.

Background: Interferon gamma release assays (IGRAs) are widely used to detect pathogen specific cellular immunity. Cytomegalovirus (CMV) is the foremost problematic viral infection in immunocompromised patients such as transplant or HIV infected patients. CMV antibody ELISAs are not able to predict CMV specific cellular immunity during immunosuppression.

Diagnosis of recent primary rubella virus infections: significance of glycoprotein-based IgM serology, IgG avidity and immunoblot analysis.

Reliable serodiagnosis of rubella virus (RV) infections requires discrimination of specific IgM induced by primary rubella from persistent, reactivated or non-specific IgM reactivity. Sera from 130 pregnant women with recent or past RV infection/vaccination, persistent IgM or negative rubella serology, 26 patients with other acute infections and 5 patients with rheumatoid factor-positivity were analyzed for RV-specific IgM by ELISA coated with whole-virus lysate or native glycoprotein, followed by determination of IgG avidity and E2-specific IgG using lysate-coated ELISA and non-reducing immunoblot. Compared to a reference μ-capture IgM ELISA, the sensitivity for diagnosing recent rubella infection/vaccination was 90.

Assessment of mumps virus-specific antibodies by different serological assays: which test correlates best with mumps immunity?

Mumps is one of the vaccine-preventable childhood diseases and it has not yet been eradicated in Germany. This raises the question as to whether the available mumps vaccines are effective enough to prevent mumps and which antibody test system allows the authentic assigning of mumps-specific immunity. In an attempt to answer this question, we analysed 227 sera samples from medical students of the University Hospital Frankfurt/Main, Germany, using different test systems: indirect immune fluorescence, neutralisation assay, routine ELISA and newly developed immunoassays, which contain the mumps nucleoprotein and the wild-type strain Enders ATCC VR106, respectively.

[Investigation of West Nile virus in central nervous system infections of unknown etiology in Ankara, Turkey].

Arthropod-borne viral infections have recently gained considerable attention and importance as re-emerging infections in a global scale. West Nile Virus (WNV), a member of Flaviviridae, is an enveloped positive strand RNA virus that is usually transmitted to humans by the bite of Culicine mosquitoes. Although the majority of the human infections are asymptomatic, WNV may also cause febrile and neuro-invasive diseases.