Coinfections and antimicrobial treatment in a cohort of falciparum malaria in a non-endemic country: a 10-year experience

INTRODUCTION

Falciparum malaria remains one of the deadliest infectious diseases worldwide. In Germany, it is mainly an imported infection among travellers. Rates of coinfection are often unknown, and a clinical rationale for the beneficial use of calculated antibiotic therapy in patients with malaria and suspected coinfection is lacking.

METHODS

We conducted an analysis of all in-patients treated with falciparum malaria at a German infectious diseases centre in vicinity to one of Europe's major airports for 2010-2019. Logistic regression and time-to-event analysis were used to evaluate predictors for bacterial coinfection, the use of antibacterial substances, as well as their influence on clinical course.

RESULTS

In total, 264 patients were included. Of those, 64% received an additional antibacterial therapy (n = 169). Twenty-nine patients (11.0%) were found to have suffered from a relevant bacterial coinfection, while only a small fraction had relevant bacteremia (n = 3, 1.4%). However, patients with severe malaria did not suffer from coinfections more frequently (p = 0.283). CRP levels were not a reliable predictor for a bacterial coinfection (OR 0.99, 95% CI 0.94-1.06, p = 0.850), while another clinical focus of infection was positively associated (OR 3.86, 95% CI 1.45-11.55, p  = 0.010).

CONCLUSION

Although bacterial coinfections were rare in patients with malaria at our centre, the risk does not seem negligible. These data point rather towards individual risk assessment in respective patients than to general empiric antibiotic use.

Pediatric cancer patients vaccinated against SARS-CoV-2-a clinical and laboratory follow-up

BACKGROUND

Vaccination against SARS-CoV-2 is recommended for cancer patients. However, long-term data on the effectiveness in the pediatric setting are lacking.

METHODS

Pediatric patients < 18 years on active treatment for cancer and without prior SARS-CoV-2 infection received three doses of an mRNA vaccine. The clinical course and humoral and cellular immunity were evaluated at the end of the follow-up period of ≥ 1 year after the third dose of vaccine.

RESULTS

SARS-CoV-2 infection occurred in 17 of 19 analyzed patients (median age 16.5 years) during the follow-up period (median 17 months), but no severe symptoms were seen. At ≥ 1 year after the last SARS-CoV-2 antigen exposure, 4 of 17 patients had received the recommended booster vaccine. At the end of the follow-up period, all evaluable 15 patients had anti-SARS-CoV-2 receptor-binding domain IgG antibodies. Twelve of the 15 patients had neutralizing antibody titers ≥ 1:10 against the Delta variant and 12/15 and 13/15 against the BA.1 and BA.5 variants, respectively. Specific T cells against SARS-CoV-2 antigens were seen in 9/13 patients.

CONCLUSIONS

Most SARS-CoV-2-vaccinated pediatric cancer patients had SARS-CoV-2 infections and limited interest in booster vaccination. At 1 year after the last antigen exposure, which was mostly an infection, humoral immune responses remained strong.

TRIAL REGISTRATION

German Clinical Trials Register DRKS00025254, May 26, 2021.

Translation of Ontological Concepts from English into German Using Commercial Translation Software and Expert Evaluation

Medical ontologies are mostly available in English. This presents a language barrier that is a limitation in research and automated processing of patient data. The manual translation of ontologies is complex and time-consuming. However, there are commercial translation tools that have shown promising results in the field of medical terminology translation. The aim of this study is to translate selected terms of the Human Phenotype Ontology (HPO) from English into German using commercial translators. Six medical experts evaluated the translation candidates in an iterative process. The results show commercial translators, with DeepL in the lead, provide translations that are positively evaluated by experts. With a broader study scope and additional optimization techniques, commercial translators could support and facilitate the process of translating medical ontologies.

Progressive loss of conserved spike protein neutralizing antibody sites in Omicron sublineages is balanced by preserved T cell immunity

Evolution of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant has led to the emergence of sublineages with different patterns of neutralizing antibody evasion. We report that Omicron BA.4/BA.5 breakthrough infection of individuals immunized with SARS-CoV-2 wild-type-strain-based mRNA vaccines results in a boost of Omicron BA.4.6, BF.7, BQ.1.1, and BA.2.75 neutralization but does not efficiently boost BA.2.75.2, XBB, or XBB.1.5 neutralization. In silico analyses showed that the Omicron spike glycoprotein lost most neutralizing B cell epitopes, especially in sublineages BA.2.75.2, XBB, and XBB.1.5. In contrast, T cell epitopes are conserved across variants including XBB.1.5. T cell responses of mRNA-vaccinated, SARS-CoV-2-naive individuals against the wild-type strain, Omicron BA.1, and BA.4/BA.5 were comparable, suggesting that T cell immunity against recent sublineages including XBB.1.5 may remain largely unaffected. While some Omicron sublineages effectively evade B cell immunity, spike-protein-specific T cell immunity, due to the nature of polymorphic cell-mediated immune responses, may continue to contribute to prevention/limitation of severe COVID-19 manifestation.

Is Olfactory Testing a Useful Diagnostic Tool to Identify SARS-CoV-2 Infections Early? A Cross-Sectional and Longitudinal Analysis

BACKGROUND

Genesis and the prognostic value of olfactory dysfunction (OD) in COVID-19 remain partially described. The objective of our study was to characterize OD during SARS-CoV-2 infection and to examine whether testing of OD may be a useful tool in clinical practice in order to early identify patients with SARS-CoV-2 infection.

METHODS

Olfactory function assessment was objectively carried out using the u-Smell-it^® test. In a cross-sectional study part, we evaluated this test in a control cohort of SARS-CoV-2 negative tested patients, who attended the University Hospital Frankfurt between May 2021 and March 2022. In a second longitudinal study part, sensitivity and specificity of OD was evaluated as a diagnostic marker of a SARS-CoV-2 infection in Frankfurt am Main, Germany in SARS-CoV-2 infected patients and their close contacts.

RESULTS

Among 494 SARS-CoV-2 negative tested patients, OD was detected in 45.7% and was found to be significantly associated with the male gender (p < 0.001), higher age (p < 0.001), cardiovascular and pulmonary comorbidities (p < 0.001; p = 0.03). Among 90 COVID-19 positive patients, OD was found in 65.6% and was significantly associated with male gender and positive smoking status (p = 0.04 each). Prevalence and severity of OD were significantly increased in infections with the Delta variant (B.1.617.2) compared to those with the Omicron variant (BA.1.1.529). Diagnostic sensitivity and specificity of OD for diagnosis of SARS-CoV-2 infection were 69% and 64%, respectively.

CONCLUSION

OD is common in COVID-19 negative and positive tested patients with significantly different prevalence rates observed between different variants. Diagnostic accuracy of OD is not high enough to implement olfactory testing as a tool in diagnostic routine to early identify patients with a SARS-CoV-2 infection.

First description of congenital toxoplasmosis after maternal coinfection with Toxoplasma gondii and severe acute respiratory syndrome coronavirus 2: a case report

BACKGROUND

Congenital toxoplasmosis can be associated with serious clinical consequences from fetus to adulthood. Hence, early detection is required to minimize severe sequelae through appropriate therapy. We describe the first case of a congenital toxoplasmosis after maternal coinfection with Toxoplasma gondii and severe acute respiratory syndrome coronavirus 2 and the challenging serological diagnosis of the disease in this context.

CASE PRESENTATION

A Caucasian boy was born at 27 weeks 2 days of gestation by cesarean section due to maternal COVID-19-related respiratory failure. Postpartum serological screening of the mother revealed a previously unrecognized active Toxoplasma gondii infection. The premature child initially tested negative for anti- Toxoplasma gondii immunoglobulin A and M antibodies 1, 2 and 4 weeks after birth, whereas immunoglobulin G antibodies were only weakly positive with no evidence of child-specific production. Neither neurological nor ophthalmological abnormalities were detected. Approximately 3 months after birth, serological testing indicated a congenital toxoplasmosis by presence of immunoglobulin A and M, in combination with a child-specific immunoglobulin G synthesis. Additionally, cerebrospinal fluid was tested positive for Toxoplasma gondii DNA. Although no clinical manifestations of congenital toxoplasmosis were detected, an antiparasitic therapy was initiated to minimize the risk of late sequelae. There were no hints for a transplacental transmission of severe acute respiratory syndrome coronavirus 2.

CONCLUSION

This case raises the awareness of possible coinfections with the risk of transplacental transmission in cases of maternal coronavirus disease 2019. The report emphasizes the need for screening vulnerable patients for toxoplasmosis in general and especially in the context of pregnancy. It becomes evident that prematurity can complicate the serological diagnosis of congenital toxoplasmosis due to a delayed antibody response. Repeated testing is recommended to carefully monitor children at risk and especially those with a history of preterm birth.

Omicron BA.2 breakthrough infection enhances cross-neutralization of BA.2.12.1 and BA.4/BA.5

BNT162b2-vaccinated individuals after Omicron BA.1 breakthrough infection have strong serum neutralizing activity against Omicron BA.1, BA.2, and previous SARS-CoV-2 variants of concern (VOCs), yet less against the highly contagious Omicron sublineages BA.4 and BA.5 that have displaced previous variants. As the latter sublineages are derived from Omicron BA.2, we characterized serum neutralizing activity of COVID-19 mRNA vaccine triple-immunized individuals who experienced BA.2 breakthrough infection. We demonstrate that sera of these individuals have broadly neutralizing activity against previous VOCs as well as all tested Omicron sublineages, including BA.2 derived variants BA.2.12.1, BA.4/BA.5. Furthermore, applying antibody depletion we showed that neutralization of BA.2 and BA.4/BA.5 sublineages by BA.2 convalescent sera is driven to a significant extent by antibodies targeting the N-terminal domain (NTD) of the spike glycoprotein. However, neutralization by Omicron BA.1 convalescent sera depends exclusively on antibodies targeting the receptor binding domain (RBD). These findings suggest that exposure to Omicron BA.2, in contrast to BA.1 spike glycoprotein, triggers significant NTD specific recall responses in vaccinated individuals and thereby enhances the neutralization of BA.4/BA.5 sublineages. Given the current epidemiology with a predominance of BA.2 derived sublineages like BA.4/BA.5 and rapidly ongoing evolution, these findings helped to inform development of our Omicron BA.4/BA.5-adapted vaccine.

Limited neutralisation of the SARS-CoV-2 Omicron subvariants BA.1 and BA.2 by convalescent and vaccine serum and monoclonal antibodies

BACKGROUND

In recent months, Omicron variants of SARS-CoV-2 have become dominant in many regions of the world, and case numbers with Omicron subvariants BA.1 and BA.2 continue to increase. Due to numerous mutations in the spike protein, the efficacy of currently available vaccines, which are based on Wuhan-Hu 1 isolate of SARS-CoV-2, is reduced, leading to breakthrough infections. Efficacy of monoclonal antibody therapy is also likely impaired.

METHODS

In our in vitro study using A549-AT cells constitutively expressing ACE2 and TMPRSS2, we determined and compared the neutralizing capacity of vaccine-elicited sera, convalescent sera and monoclonal antibodies against authentic SARS-CoV-2 Omicron BA.1 and BA.2 compared with Delta.

FINDINGS

Almost no neutralisation of Omicron BA.1 and BA.2 was observed using sera from individuals vaccinated with two doses 6 months earlier, regardless of the type of vaccine taken. Shortly after the booster dose, most sera from triple BNT162b2-vaccinated individuals were able to neutralise both Omicron variants. In line with waning antibody levels three months after the booster, only weak residual neutralisation was observed for BA.1 (26%, n = 34, 0 median NT₅₀) and BA.2 (44%, n = 34, 0 median NT₅₀). In addition, BA.1 but not BA.2 was resistant to the neutralising monoclonal antibodies casirivimab/imdevimab, while BA.2 exhibited almost a complete evasion from the neutralisation induced by sotrovimab.

INTERPRETATION

Both SARS-CoV-2 Omicron subvariants BA.1 and BA.2 escape antibody-mediated neutralisation elicited by vaccination, previous infection with SARS-CoV-2, and monoclonal antibodies. Waning immunity renders the majority of tested sera obtained three months after booster vaccination negative in BA.1 and BA.2 neutralisation. Omicron subvariant specific resistance to the monoclonal antibodies casirivimab/imdevimab and sotrovimab emphasizes the importance of genotype-surveillance and guided application.

FUNDING

This study was supported in part by the Goethe-Corona-Fund of the Goethe University Frankfurt (M.W.) and the Federal Ministry of Education and Research (COVIDready; grant 02WRS1621C (M.W.).

Longitudinal Immune Response to 3 Doses of Messenger RNA Vaccine Against Coronavirus Disease 2019 (COVID-19) in Pediatric Patients Receiving Chemotherapy for Cancer

Our study in 21 pediatric cancer patients demonstrates that 3 doses of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) messenger RNA vaccine (BioNTech/Pfizer) elicited both humoral and cellular immunity in most patients during chemotherapy. Immunity was stronger in children with solid tumors and during maintenance therapy compared to those with hematological malignancies or during intensive chemotherapy. Clinical Trials Registration.ȃGerman Registry for Clinical Trials (DRKS00025254).

Characterization of the Antibody and Interferon-Gamma Release Response after a Second COVID-19 Booster Vaccination

The emergence of SARS-CoV-2 Omicron subvariants prompted countries to call for accelerated booster vaccinations to limit disease and transmission. Here, we characterized correlates of protection over time after the second booster or after Omicron BA.1 infection comparing variants of concern (VOCs). Sera from subjects before and two and seven weeks after the second booster or after Omicron infection were examined for the level of Spike receptor-binding-domain (RBD)-specific antibodies. Furthermore, neutralizing antibodies (nABs) were characterized in in vitro neutralization assays comparing the variants of concern Alpha, Beta, Delta, and Omicron BA.1 and BA.2 against the ancestral strain B.1. Here, the second booster resulted in an increase in anti-RBD-IgG-antibodies, remaining nearly constant over time, accompanied by an increase in nABs against B.1 and the VOCs Alpha, Beta, Delta, and Omicron BA.1 and BA.2. However, compared to B.1, the neutralizing capacity against the Omicron subvariants remained low and was limited after the second booster vaccination. This indicates that antibody-mediated protection against infection with this VOC is unlikely, as evidenced by the fact that three individuals of our study cohort became infected with Omicron BA.1 after the second booster. T cell activation was measured by interferon-gamma release assays in a subgroup of subjects and was increased in all subjects tested after the second booster vaccination, correlating with the amount of Spike-specific antibodies. In subjects with Omicron BA.1 breakthrough infection, a significant increase in nABs to all VOCs studied was observed independently of booster vaccinations. Taken together, our data indicate that a second booster or Omicron BA.1 infection mediate a substantial increase in anti-Spike IgG antibodies; however, infection with Omicron BA.1 induced a stronger increase in neutralizing antibodies against the different VOCs

Low But Recoverable Markers of Humoral Immune Response to BNT162b2 in Elderly LTCF Residents Five to Seven Months After Two-Dose Vaccination

The immune response is known to wane after vaccination with BNT162b2, but the role of age, morbidity and body composition is not well understood. We conducted a cross-sectional study in long-term care facilities (LTCFs) for the elderly. All study participants had completed two-dose vaccination with BNT162b2 five to 7 months before sample collection. In 298 residents (median age 86 years, range 75–101), anti-SARS-CoV-2 rector binding IgG antibody (anti-RBD-IgG) concentrations were low and inversely correlated with age (mean 51.60 BAU/ml). We compared the results to Health Care Workers (HCW) aged 18–70 years (n = 114, median age: 53 years), who had a higher mean anti-RBD-IgG concentration of 156.99 BAU/ml. Neutralization against the Delta variant was low in both groups (9.5% in LTCF residents and 31.6% in HCWs). The Charlson Comorbidity Index was inversely correlated with anti-RBD-IgG, but not the body mass index (BMI). A control group of 14 LTCF residents with known breakthrough infection had significant higher antibody concentrations (mean 3,199.65 BAU/ml), and 85.7% had detectable neutralization against the Delta variant. Our results demonstrate low but recoverable markers of immunity in LTCF residents five to 7 months after vaccination.

Omicron BA.1 breakthrough infection drives cross-variant neutralization and memory B cell formation against conserved epitopes

Omicron is the evolutionarily most distinct SARS-CoV-2 variant of concern (VOC) to date. We report that Omicron BA.1 breakthrough infection in BNT162b2-vaccinated individuals resulted in strong neutralizing activity against Omicron BA.1, BA.2 and previous SARS-CoV-2 VOCs, but not against the Omicron sublineages BA.4 and BA.5. BA.1 breakthrough infection induced a robust recall response, primarily expanding B_MEM cells against epitopes shared broadly amongst variants, rather than inducing BA.1-specific B cells. The vaccination-imprinted B_MEM cell pool had sufficient plasticity to be remodeled by heterologous SARS-CoV-2 spike glycoprotein exposure. While selective amplification of B_MEM cells recognizing shared epitopes allows for effective neutralization of most variants that evade previously established immunity, susceptibility to escape by variants that acquire alterations at hitherto conserved sites may be heightened.

SARS-CoV-2 screening strategies for returning international travellers: Evaluation of a rapid antigen test approach

Background

International travel poses the risk of importing SARS-CoV-2 infections and introducing new viral variants into the country of destination. Established measures include mandatory quarantine with the opportunity to abbreviate it with a negative rapid antigen test (RAT).

Methods

A total of 1,488 returnees were tested for SARS-CoV-2 with both PCR and RAT no earlier than 5 days after arrival. We assessed the sensitivity and specificity of the RAT. Positive samples were evaluated for infectivity in vitro in a cell culture outgrowth assay. We tracked if participants who tested negative were reported positive within 2 weeks of the initial test.

Results

Potential infectiousness was determined based on symptom onset analysis, resulting in a sensitivity of the antigen test of 89% in terms of infectivity. The specificity was 100%. All positive outgrowth assays were preceded by a positive RAT, indicating that all participants with proven in vitro infectivity were correctly identified. None of the negative participants tested positive during the follow-up.

Conclusions

RAT no earlier than the 5th day after arrival was a reliable method for detecting infectious travellers and can be recommended as an appropriate method for managing SARS-CoV-2 travel restrictions. Compliance to the regulations and a high standard of test quality must be ensured.

Self-Collected Samples to Detect SARS-CoV-2: Direct Comparison of Saliva, Tongue Swab, Nasal Swab, Chewed Cotton Pads and Gargle Lavage

Testing for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) by RT-PCR is a vital public health tool in the pandemic. Self-collected samples are increasingly used as an alternative to nasopharyngeal swabs. Several studies suggested that they are sufficiently sensitive to be a useful alternative. However, there are limited data directly comparing several different types of self-collected materials to determine which material is preferable. A total of 102 predominantly symptomatic adults with a confirmed SARS-CoV-2 infection self-collected native saliva, a tongue swab, a mid-turbinate nasal swab, saliva obtained by chewing a cotton pad and gargle lavage, within 48 h of initial diagnosis. Sample collection was unsupervised. Both native saliva and gargling with tap water had high diagnostic sensitivity of 92.8% and 89.1%, respectively. Nasal swabs had a sensitivity of 85.1%, which was not significantly inferior to saliva (p = 0.092), but 16.6% of participants reported they had difficult in self-collection of this sample. A tongue swab and saliva obtained by chewing a cotton pad had a significantly lower sensitivity of 74.2% and 70.2%, respectively. Diagnostic sensitivity was not related to the presence of clinical symptoms or to age. When comparing self-collected specimens from different material, saliva, gargle lavage or mid-turbinate nasal swabs may be considered for most symptomatic patients. However, complementary experiments are required to verify that differences in performance observed among the five sampling modes were not attributed to collection impairment.

COVID-19 among children seeking primary paediatric care with signs of an acute infection

AIM

It can be challenging to distinguish COVID-19 in children from other common infections. We set out to determine the rate at which children consulting a primary care paediatrician with an acute infection are infected with SARS-CoV-2 and to compare distinct findings.

METHOD

In seven out-patient clinics, children aged 0-13 years with any new respiratory or gastrointestinal symptoms and presumed infection were invited to be tested for SARS-CoV-2. Factors that were correlated with testing positive were determined. Samples were collected from 25 January 2021 to 01 April 2021.

RESULTS

Seven hundred and eighty-three children participated in the study (median age 3 years and 0 months, range 1 month to 12 years and 11 months). Three hundred and fifty-eight were female (45.7%). SARS-CoV-2 RNA was detected in 19 (2.4%). The most common symptoms in children with as well as without detectable SARS-CoV-2 RNA were rhinitis, fever and cough. Known recent exposure to a case of COVID-19 was significantly correlated with testing positive, but symptoms or clinical findings were not.

CONCLUSION

COVID-19 among the children with symptoms of an acute infection was uncommon, and the clinical presentation did not differ significantly between children with and without evidence of an infection with SARS-CoV-2.

Limited neutralization of authentic SARS-CoV-2 variants carrying E484K in vitro

Whether monoclonal antibodies are able to neutralise SARS-CoV-2 variants of concern has been investigated using pseudoviruses. In this study we show that bamlanivimab, casirivimab, and imdevimab efficiently neutralise authentic SARS-CoV-2 including variant B.1.1.7 (Alpha) but variants B.1.351 (Beta) and P.2 (Zeta) were resistant against bamlanivimab and partially to casirivimab.

Evaluation of stability and inactivation methods of SARS-CoV-2 in context of laboratory settings

The novel coronavirus SARS-CoV-2 is the causative agent of the acute respiratory disease COVID-19, which has become a global concern due to its rapid spread. Laboratory work with SARS-CoV-2 in a laboratory setting was rated to biosafety level 3 (BSL-3) biocontainment level. However, certain research applications in particular in molecular biology require incomplete denaturation of the proteins, which might cause safety issues handling contaminated samples. In this study, we evaluated lysis buffers that are commonly used in molecular biological laboratories for their ability to inactivate SARS-CoV-2. In addition, viral stability in cell culture media at 4 °C and on display glass and plastic surfaces used in laboratory environment was analyzed. Furthermore, we evaluated chemical and non-chemical inactivation methods including heat inactivation, UV-C light, addition of ethanol, acetone-methanol, and PFA, which might be used as a subsequent inactivation step in the case of insufficient inactivation. We infected susceptible Caco-2 and Vero cells with pre-treated SARS-CoV-2 and determined the tissue culture infection dose 50 (TCID₅₀) using crystal violet staining and microscopy. In addition, lysates of infected cells and virus containing supernatant were subjected to RT-qPCR analysis. We have found that guanidine thiocyanate and most of the tested detergent containing lysis buffers were effective in inactivation of SARS-CoV-2, however, the M-PER lysis buffer containing a proprietary detergent failed to inactivate the virus. In conclusion, careful evaluation of the used inactivation methods is required especially for non-denaturing buffers. Additional inactivation steps might be necessary before removal of lysed viral samples from BSL-3.

Pediatrics and COVID-19

Viral respiratory tract infections are prevalent in children. They have substantial effects on childhood morbidity throughout the world, especially in developing countries. In this chapter, we describe the preliminary characteristics of pediatric COVID-19 and discover that severe and critical disease in children is rare. Many children remain asymptomatic. The reason why severity increases with progressing age and largely spares children is not yet known. In the search for possible explanations, we explore key differences between the pediatric and adult immune responses to new pathogens, and in host factors, such as ACE2 abundance.

Comparative analysis of point-of-care, high-throughput and laboratory-developed SARS-CoV-2 nucleic acid amplification tests (NATs)

Multiple nucleic acid amplification tests (NATs) are available for the detection of SARS-CoV-2 in clinical specimens, including Laboratory Developed Tests (LDT), commercial high-throughput assays and point-of-care tests. Some assays were just recently released and there is limited data on their clinical performance. We compared the Xpert® Xpress SARS-CoV-2 (Cepheid) and Vivalytic VRI Panel (Schnelltest COVID-19) (Bosch) point-of-care tests with four high-throughput assays and one LDT, the cobas® SARS-CoV-2 test (Roche), the Allplex™ 2019-nCoV Assay (Seegene), the SARS-CoV-2 AMP (Abbott) Kit, the RealStar® SARS-CoV-2 RT-PCR Kit 1.0 (altona) as well as an assay using a SARS-CoV-2 RdRP gene specific primer and probe set. Samples from patients with confirmed SARS-CoV-2 infection, samples from the first and second SARS-CoV-2-PCR External Quality Assessment (EQA) (INSTAND e.V.) and a 10-fold serial dilution of a SARS-CoV-2 cell culture (SARS-CoV-2 Frankfurt 1) supernatant were examined. We determined that the NAT assays examined had a high specificity. Assays using the N gene as target demonstrated the highest sensitivity in the serial dilution panel, while all examined NAT assays showed a comparable sensitivity when testing clinical and EQA samples.

The Comparative Clinical Performance of Four SARS-CoV-2 Rapid Antigen Tests and Their Correlation to Infectivity In Vitro

Due to globally rising numbers of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, resources for real-time reverse-transcription polymerase chain reaction (rRT-PCR)-based testing have been exhausted. In order to meet the demands of testing and reduce transmission, SARS-CoV-2 antigen-detecting rapid diagnostic tests (Ag-RDTs) are being considered. These tests are fast, inexpensive, and simple to use, but whether they detect potentially infectious cases has not been well studied. We evaluated three lateral flow assays (RIDA®QUICK SARS-CoV-2 Antigen (R-Biopharm), SARS-CoV-2 Rapid Antigen Test (Roche)), and NADAL® COVID-19 Ag Test (Nal von Minden GmbH, Regensburg, Germany) and one microfluidic immunofluorescence assay (SARS-CoV-2 Ag Test (LumiraDx GmbH, Cologne, Germany)) using 100 clinical samples. Diagnostic rRT-PCR and cell culture testing as a marker for infectivity were performed in parallel. The overall Ag-RDT sensitivity for rRT-PCR-positive samples ranged from 24.3% to 50%. However, for samples with a viral load of more than 6 log10 RNA copies/mL (22/100), typically seen in infectious individuals, Ag-RDT positivity was between 81.8% and 100%. Only 51.6% (33/64) of the rRT-PCR-positive samples were infectious in cell culture. In contrast, three Ag-RDTs demonstrated a more significant correlation with cell culture infectivity (61.8-82.4%). Our findings suggest that large-scale SARS-CoV-2 Ag-RDT-based testing can be considered for detecting potentially infective individuals and reducing the virus spread.

Longitudinal testing for respiratory and gastrointestinal shedding of SARS-CoV-2 in day care centres in Hesse, Germany

Background

With the pandemic of SARS-CoV-2 ongoing in Europe in June of 2020, day care centres were reopened in the state of Hesse, Germany, after the lockdown. The role young children play in the dynamics of the transmission was unknown.

Methods

We conducted a longitudinal study over a period of 12 weeks and two days (18 ^th of June 2020 to 10 ^th of September, 2020) to screen attendees and staff from day care centres in the state of Hesse, Germany, for both respiratory and gastrointestinal shedding of SARS-CoV-2. 859 children (age range 3 months to 8 years) and 376 staff members from 50 day care centres, which were chosen representatively from throughout the state, participated in the study. Parents were asked to perform both a buccal mucosa and an anal swab on their children once a week. Staff were asked to self-administer the swabs. RT-PCRs for SARS-CoV-2 were performed in a multiple-swab pooling protocol.

Results

7,366 buccal mucosa swabs and 5,907 anal swabs were analysed. No respiratory or gastrointestinal shedding of SARS-CoV-2 was detected in any of the children. Shedding of SARS-CoV-2 could be detected in two staff members from distinct day care centres. One was asymptomatic at the time of testing, and one was symptomatic and did not attend the facility on that day.

Conclusion

Detection of either respiratory or gastrointestinal shedding of SARS-CoV-2 RNA in children and staff members attending day care centres was rare in the context of limited community activity and with infection prevention measures in the facilities in place.

Evaluation of a SARS-CoV-2 rapid antigen test: Potential to help reduce community spread?

•

Robust, cheap and easy-to use surveillance tests are needed to help control SARS-CoV-2 spread in the community.

•

Antigen tests can be employed at higher frequency for surveillance purposes of asymptomatic and pre-symptomatic individuals.

•

Despite lower sensitivity, frequently applied antigen tests might help to detect infected individuals and reduce transmission.

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can spread from symptomatic patients with COVID-19, but also from asymptomatic individuals. Therefore, robust surveillance and timely interventions are essential for the control of virus spread within the community. In this regard the frequency of testing and speed of reporting, but not the test sensitivity alone, play a crucial role.

Objectives

In order to reduce the costs and meet the expanding demands in real-time RT-PCR (rRT-PCR) testing for SARS-CoV-2, complementary assays, such as rapid antigen tests, have been developed. Rigorous analysis under varying conditions is required to assess the clinical performance of these tests and to ensure reproducible results.

Results

We evaluated the sensitivity and specificity of a recently licensed rapid antigen test using 137 clinical samples in two institutions. Test sensitivity was between 88.2–89.6 % when applied to samples with viral loads typically seen in infectious patients. Of 32 rRT-PCR positive samples, 19 demonstrated infectivity in cell culture, and 84 % of these samples were reactive with the antigen test. Seven full-genome sequenced SARS-CoV-2 isolates and SARS-CoV-1 were detected with this antigen test, with no cross-reactivity against other common respiratory viruses.

Conclusions

Numerous antigen tests are available for SARS-CoV-2 testing and their performance to detect infectious individuals may vary. Head-to-head comparison along with cell culture testing for infectivity may prove useful to identify better performing antigen tests. The antigen test analyzed in this study is easy-to-use, inexpensive, and scalable. It can be helpful in monitoring infection trends and thus has potential to reduce transmission.

[The virology of SARS-CoV-2]

Das neue „severe acute respiratory syndrome coronavirus 2“ (SARS-CoV-2) hat tief greifende Auswirkungen auf Gesellschaft, Wirtschaft und medizinische Versorgung. Umso wichtiger ist es, die Eigenschaften des Virus zu verstehen und diagnostisch, therapeutisch wie auch epidemiologisch zu nutzen. Im vorliegenden Beitrag wird zunächst die medizinische Bedeutung der Coronaviren im Allgemeinen erläutert. Danach wird auf das „angiotensin-converting enzyme 2“ (ACE2) als Bindungsstelle von SARS-CoV‑2 sowie dessen möglichen Einfluss auf die Erkrankungssuszeptibilität eingegangen. Als diagnostischer Goldstandard für den Nachweis einer aktiven SARS-CoV-2-Infektion gilt der Erregerdirektnachweis mit Nukleinsäureamplifikationstechniken. Zu Beginn der Symptome ist ein Abstrich der oberen Luftwege aufgrund der dann hohen Viruslast besonders geeignet. Im späteren Verlauf kann der Direktnachweis über Proben aus den unteren Atemwegen oder über einen Stuhl- bzw. Analabstrich gelingen. Antigen- oder Antikörper(AK)-Tests können den Erregerdirektnachweis nicht ersetzen. Insbesondere für epidemiologische Fragestellungen ist aber der Nachweis von Immunglobulin-G-AK von Interesse (Serokonversionszeit von teils mehreren Wochen). Der „plaque reduction neutralization test“ weist ausschließlich AK nach, die Viren neutralisieren. Das Verfahren ist aber aufwendig. Zudem ist die Bedeutung dieser AK bezüglich der Immunität gegen eine Zweitinfektion unsicher. Dank moderner Technik sind bereits Tausende SARS-CoV-2-Sequenzen verfügbar, die eine Genomvariabilität zeigen. Die Mutation D614G in den „S spikes“ scheint eine höhere Infektiosität zu bedingen. Mutationen können die Diagnostik und Therapie beeinträchtigen, was ein Monitoring erforderlich macht.

Novel multiple swab method enables high efficiency in SARS-CoV-2 screenings without loss of sensitivity for screening of a complete population

Background

In the pandemic, testing for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) by real‐time polymerase chain reaction is one of the pillars on which countermeasures are based. Factors limiting the output of laboratories interfere with the effectiveness of public health measures. Conserving reagents by pooling samples in low‐probability settings is proposed but may cause dilution and loss of sensitivity. Blood transfusion services had experience in performance of high throughput nucleic acid testing (NAT) analysis and can support the national health system by screening of the inhabitants for SARS‐COV‐2.

Methods

We evaluated a new approach of a multiple‐swab method by simultaneously incubating multiple respiratory swabs in a single tube. Analytical sensitivity was constant up to a total number of 50 swabs. It was consequently applied in the testing of 50 symptomatic patients (5‐sample pools) as well as 100 asymptomatic residents of a nursing home (10‐sample pools).

Results

The novel method did not cause false‐negative results with nonsignificantly differing cycle threshold values between single‐swab and multiple‐swab NAT. In two routine applications, all minipools containing positive patient samples were correctly identified.

Conclusions

The new method enables countries to increase the total number of testing significantly. The multiple‐swab method is able to screen system relevant groups of employees frequently. The example in Germany shows that blood transfusion services can support general health systems with their experience in NAT and their high‐throughput instruments. Screening of a huge number of inhabitants is currently the only option to prevent a second infection wave and enable exit strategies in many countries.

Thirty years of CMV seroprevalence-a longitudinal analysis in a German university hospital

Human cytomegalovirus (CMV) is a significant cause of morbidity and mortality in patient groups at risk. We have previously shown that the anti-CMV IgG seroprevalence in an urban region of Germany has changed over the last decades. Overall, a decline from 63.7 to 57.25% had been observed between 1988–1997 and 1998–2008 (p < 0,001). Here, we continuously follow the trends to the most recent decade 2009 to 2018. In a retrospective analysis, we determined the seroprevalence of CMV IgG antibodies in our patient cohort, stratified by gender and selected groups at risk (e.g., patients with HIV infection; women of childbearing age). The overall prevalence of anti-CMV IgG non-significantly declined further from 57.25% in 1998–2008 to 56.48% in 2009–2018 (p = 0.881). Looking at gender differences, overall CMV seroprevalence in males declined to 52.82% (from 55.54% in 1998–2008; p = 0.0254), while it non-significantly increased in females to 59.80%. The high seroprevalence in patients with a known HIV infection further increased from 87.46% in 1998–2008 to 92.93% in the current period (p = 0.9999). In women of childbearing age, no significant changes over the last three decades could be observed. The CMV seroprevalence in oncological patients was determined to be 60.64%. Overall, the former significant decline of CMV seroprevalence between the decades 1988–1997 and 1998–2008 in this urban region of Germany slowed down to a non-significant decrease of 0.77% (1998–2008 vs. 2009–2018). This might be an indicator that CMV seroprevalence has reached a plateau.