Effects of infection control measures towards preventing SARS-CoV-2 outbreaks in a German choir boarding school from March 2020 to April 2022

Background

Singing in a choir was associated with larger outbreaks in the beginning of the SARS-CoV-2 pandemic.

Materials and methods

We report on the effect and acceptance of various infection control measures on the occurrence of SARS-CoV-2 infections in the world famous Domspatzen boys' choir from March 2020 to April 2022.

Results

In addition to basic general hygiene measures, systematic rRT-PCR testing and scientifically approved concepts of distancing during singing were applied. While single infections of choir members could not be avoided, singing-related outbreaks were not observed. Until the Omicron variant emerged, potential transmission of SARS-CoV-2 in the school was limited to only one case. Incidences at the school were never higher than in the comparable general population until then. While the impact of the pandemic on daily life and singing was rated as severe, especially by staff members, most students agreed with the usefulness of protection measures and rated them as acceptable. Students viewed regular testing as the most important tool to increase safety in the school.

Discussion

A bundle of infection control measures including regular testing can prevent outbreaks of SARS-CoV-2 even in the setting of choir singing. Measures are acceptable for choir members if they allow to continue with singing and performing.

Analysis of COVID-19 Infection Chains in a School Setting: Data From a School-Based rRT-PCR-Gargle Pool Test System

BACKGROUND

School testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was implemented in some countries to monitor and prevent SARS-CoV-2 transmissions. Here, we analyze infection chains in primary schools and household members of infected students based on systematic real-time reverse-transcriptase polymerase-chain-reaction (rRT-PCR)-gargle pool testing.

METHODS

Students and school staff (N = 4300) of all 38 primary schools in the rural county of Cham, Germany, were tested twice per week with a gargle pool rRT-PCR system from April to July of 2021. Infection chains of all 8 positive cases identified by school testing were followed up.

RESULTS

In total, 8 positive cases were found by gargle pool PCR testing based on 96,764 school tests. While no transmissions occurred in the school setting, 20 of 27 household members of the 8 cases tested positive. The overall attack rate was 74.1% in families.

CONCLUSIONS

No school outbreaks occurred during the study period. All cases but 1 were initially picked up by school testing. No transmission from school to families was observed.

Results of WICOVIR Gargle Pool PCR Testing in German Schools Based on the First 100,000 Tests

Background: Opening schools and keeping children safe from SARS-CoV-2 infections at the same time is urgently needed to protect children from direct and indirect consequences of the COVID-19 pandemic. To achieve this goal, a safe, efficient, and cost-effective SARS-CoV-2 testing system for schools in addition to standard hygiene measures is necessary. Methods: We implemented the screening WICOVIR concept for schools in the southeast of Germany, which is based on gargling at home, pooling of samples in schools, and assessment of SARS-CoV-2 by pool rRT-PCR, performed decentralized in numerous participating laboratories. Depooling was performed if pools were positive, and results were transmitted with software specifically developed for the project within a day. Here, we report the results after the first 13 weeks in the project. Findings: We developed and implemented the proof-of-concept test system within a pilot phase of 7 weeks based on almost 17,000 participants. After 6 weeks in the main phase of the project, we performed >100,000 tests in total, analyzed in 7,896 pools, identifying 19 cases in >100 participating schools. On average, positive children showed an individual CT value of 31 when identified in the pools. Up to 30 samples were pooled (mean 13) in general, based on school classes and attached school staff. All three participating laboratories detected positive samples reliably with their previously established rRT-PCR standard protocols. When self-administered antigen tests were performed concomitantly in positive cases, only one of these eight tests was positive, and when antigen tests performed after positive pool rRT-PCR results were already known were included, 3 out of 11 truly positive tests were also identified by antigen testing. After 3 weeks of repetitive WICOVIR testing twice weekly, the detection rate of positive children in that cohort decreased significantly from 0.042 to 0.012 (p = 0.008). Interpretation: Repeated gargle pool rRT-PCR testing can be implemented quickly in schools. It is an effective, valid, and well-received test system for schools, superior to antigen tests in sensitivity, acceptance, and costs.

Symptoms, SARS-CoV-2 Antibodies, and Neutralization Capacity in a Cross Sectional-Population of German Children

Background: Children and youth are affected rather mildly in the acute phase of COVID-19 and thus, SARS-CoV-2 infection infection may easily be overlooked. In the light of current discussions on the vaccinations of children it seems necessary to better identify children who are immune against SARS-CoV-2 due to a previous infection and to better understand COVID-19 related immune reactions in children. Methods: In a cross-sectional design, children aged 1-17 were recruited through primary care pediatricians for the study (a) randomly, if they had an appointment for a regular health check-up or (b) if parents and children volunteered and actively wanted to participate in the study. Symptoms were recorded and two antibody tests were performed in parallel directed against S (in house test) and N (Roche Elecsys) viral proteins. In children with antibody response in either test, neutralization activity was determined. Results: We identified antibodies against SARS-CoV-2 in 162 of 2,832 eligible children (5.7%) between end of May and end of July 2020 in three, in part strongly affected regions of Bavaria in the first wave of the pandemic. Approximately 60% of antibody positive children (n = 97) showed high levels (>97th percentile) of antibodies against N-protein, and for the S-protein, similar results were found. Sufficient neutralizing activity was detected for only 135 antibody positive children (86%), irrespective of age and sex. Initial COVID-19 symptoms were unspecific in children except for the loss of smell and taste and unrelated to antibody responses or neutralization capacity. Approximately 30% of PCR positive children did not show seroconversion in our small subsample in which PCR tests were performed. Conclusions: Symptoms of SARS-CoV-2 infections are unspecific in children and antibody responses show a dichotomous structure with strong responses in many and no detectable antibodies in PCR positive children and missing neutralization activity in a relevant proportion of the young population.

Effect of ozone, chlorine and hydrogen peroxide on the elimination of colour in treated textile wastewater by MBR

In treating textile wastewater, the application of membrane bioreactor (MBR) technology showed high efficiency in COD and BOD5 removal. However, insufficient colour removal was achieved for possible reuse. The aim of the work presented in this paper was to test the performance of chemical advanced oxidation on the elimination of the colour downstream of an MBR. To improve the quality of the membrane bioreactor effluent three different oxidation treatments were tested at lab-scale: ozonation, chlorination and hydrogen peroxide oxidation. Colour, COD and BOD5 were controlled in order to assess the effectiveness of each process. For chlorination, even with 250 mg/L (active chlorine) only 80% colour removal (SACin = 14; SACout = 2.8) was achieved which is considered unsatisfactory. For hydrogen peroxide, the colour removal was even poorer; it was just 10% at a concentration of 250 mg/L. In contrast, good results were obtained by ozonation. By using only 38 mg/L within 20 minutes, it was possible to achieve the reuse recommendation with a satisfactory colour removal of 93% (SACin = 14; SACout = 0.98). The results showed that ozonation was the most promising method.

Hemocyanins in spiders, VI[1]. Comparison of the polypeptide chains of Eurypelma californicum hemocyanin

The subunits of the hemocyanin from the tarantula, Eurypelma californicum, were isolated, following dissociation at pH 9.6, by a sequence of chromatographic and electrophoretic steps. Fraction 2 (containing two chains, a and c2) and the constituent polypeptide chains of the dimeric subunit 4D (b and c4) were resolved by anion exchange chromatography at pH 8.9 and 6.5, respectively. Since c2 and c4 have different electrophoretic mobilities in polyacrylamide gradient gels, the total number of different polypeptide chains is seven. The amino acid compositions of the seven chains are reported. There are major differences for at least half of the amino acids, while more consistent proportions become evident, if the amino acids are grouped by types of side chains. The N-terminal amino acid is proline in the case of chains b and e,, while no end group called be detected in any of the other chains by different methods. The C-terminal end group was found to be valine in both chains d and e. Cleavage by 70% formic acid, and by cyanogen bromide in formic acid results in fragmentation patterns distinct for each chain. After cyanogen bromide cleavage, the two largest peptides of each chain are of molecular weight near 2400. Tryptic fingerprints also reveal significant differences between all chains. Subunit heterogeneity of Eurypelma hemocyanin is clearly not the consequence of secondary modifications, but resides in major differences of the amino acid sequences.