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In the ongoing SARS-CoV-2 pandemic, there is a need for new strategies for surveillance and identification of arising infection waves. Reported cases of new infections based on individual testing are soon deemed inaccurate due to ever changing regulations and limited testing capacity. Wastewater based epidemiology is one promising solution that can be broadly applied with low efforts in comparison to current large-scale testing of individuals. Here, we are combining local wastewater data from the city of Dresden (Germany) along with reported cases and vaccination data from a central database (Robert-Koch-Institute) with virus variant information to investigate the correlation of virus concentrations in the wastewater and reported SARS-CoV-2 cases. In particular, we compared Linear Regression and Machine Learning (ML) models, which are both revealing an existing correlation of virus particles in wastewater and reported cases. Our findings demonstrate that the different virus variants of concern (Alpha, Delta, BA.1, and BA.2) contribute differently over time and parameters vary between variants, as well. By comparing the Linear Regression and ML-based models, we observed that ML can achieve a good fit for training data, but Linear Regression is a more robust tool, especially for new virus variants. We hereby conclude that deriving the rate of new infections from local wastewater by applying Linear Regression may be a robust approximation of tracing the state of the pandemic for practitioners and policy makers alike.
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ObjectivesPrevious data indicate that children might play a less crucial role in SARS-CoV-2 transmission than initially assumed. We conducted a study to gain further knowledge on prevalence, transmission and spread of SARS-CoV-2 among preschool children, their parents and caretakers. MethodsChildren, their parents and care givers in 14 childcare facilities in Dresden, Saxony/ Germany were invited to participate in the KiTaCoviDD19-study between July 2020 and January 2021. Seroprevalence of SARS-CoV-2 antibodies was assessed up to 4 times during the study period in all participating adults and personal characteristics as well as epidemiological information of personal SARS-CoV-2 history were obtained. Stool viral shedding of SARS-CoV-2 was analyzed every 2-4 weeks in all participating children. ResultsIn total, 318 children, 299 parents and 233 childcare workers were enrolled. The percentage of seropositive adults and SARS-CoV-2 positive detected children rose considerably by January 2021. However, the rate of SARS-CoV-2 positive children was considerably lower than the rate of seropositive adults. Overall, we detected a maximum of three connected cases in children. About 50% of SARS-CoV-2 infections in children could not be connected to a secondary case within our study population. ConclusionThe study could not provide evidence for a relevant asymptomatic ("silent") spread of SARS-CoV-2 in childcare facilities, neither in a low nor a high prevalence setting. This finding adds to the evidence that childcare and educational settings do not play a crucial role in driving the SARS-CoV-2 pandemic. Table of Contents SummaryThis longitudinal study among children, parents and childcare workers provides further insight on SARS-CoV-2 prevalence and transmission within childcare facilities. Whats Known on This SubjectBased on age distribution of SARS-CoV-2 infections and previous data of very limited spread of COVID-19 among primary and secondary schools there is reason to believe that children play a less crucial role in SARS-CoV-2 transmission than initially assumed. What This Study AddsPreviously published studies focus mainly on SARS-CoV-2 transmission in schools. This longitudinal study provides information on prevalence, transmission and spread of SARS-CoV-2 within childcare facilities during low- and high-prevalence settings.
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PurposeComparing seroprevalence and antibody kinetics in three different commercially available assays for SARS-CoV-2. MethodsSerostatus of COVID-19 patients was analyzed 5 months and 10 months after their infection, using three different assays: Diasorin LIAISON(R), Euroimmun(R), Abbott Diagnostics(R) ARCHITECT. ResultsSeropositivity at baseline differed significantly depending on the assay (Diasorin 81%, Euroimmun 83%, Abbott 59%). At follow-up antibody levels detected in the Diasorin assay were stable, while there was a significant loss in seropositivity in the Euroimmun and Abbott assays. ConclusionThere are significant differences in SARS-CoV-2 antibody kinetics based on the specific assay used. Trial registration number, date of registrationDRKS00022549, 29.07.2020 "retrospectively registered"
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BackgroundWith increasing rates of SARS-CoV-2 infections and the intention to avoid a lock-down, the risks for the working population are of great interest. No large studies have been conducted which allow risk assessment for this population. MethodsDKMS is a non-profit donor center for stem cell donation and reaches out to registered volunteers between 18 and 61 years of age. To identify risk factors for severe COVID-19 courses in this population we performed a cross-sectional study. Self-reported data on oro- or nasopharyngeal swabs, risk factors, symptoms and treatment were collected with a health questionnaire and linked to existing genetic data. We fitted multivariable logistic regression models for the risk of contracting SARS-CoV-2, risk of severe respiratory infection and risk of hospitalization. FindingsOf 4,440,895 contacted volunteers 924,660 (20.8%) participated in the study. Among 157,544 participants tested, 7,948 reported SARS-CoV-2 detection. Of those, 947 participants (11.9%) reported an asymptomatic course, 5,014 (63.1%) mild/moderate respiratory infections, and 1,987 (25%) severe respiratory tract infections. In total, 286 participants (3.6%) were hospitalized for respiratory tract infections. The risk of hospitalization in comparison to a 20-year old person of normal weight was 2.1-fold higher (95%-CI, 1.2-3.69, p=0.01) for a person of same age with a BMI between 35-40 kg/m2, it was 5.33-fold higher (95%-CI, 2.92-9.70, p<0.001) for a 55-year old person with normal weight and 11.2-fold higher (95%-CI, 10.1-14.6, p<0.001) for a 55-year old person with a BMI between 35-40 kg/m2. Blood group A was associated with a 1.15-fold higher risk for contracting SARS-CoV-2 (95%-CI 1.08-1.22, p<0.001) than blood group O but did not impact COVID-19 severity. InterpretationIn this relatively healthy population, the risk for hospitalizations due to SARS-CoV-2 infections was moderate. Age and BMI were major risk factors. These data may help to tailor risk-stratified preventive measures. FundingDKMS initiated and conducted this study. The Federal Ministry of Education and Research (BMBF) supported the study by a research grant (COVID-19 call (202), reference number 01KI20177).
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BackgroundSchool closures are part of the SARS-CoV-2 pandemic control measures in many countries, based on the assumption that children play a similar role in transmitting SARS-CoV-2 as they do in transmitting influenza. We therefore performed a SARS-CoV-2 seropraevalence-study in students and teachers to assess their role in the SARS-CoV-2 transmission. MethodsStudents grade 8-11 and their teachers in 13 secondary schools in eastern Saxony, Germany, were invited to participate in the SchoolCoviDD19 study. Blood samples were collected between May 25th and June 30th, 2020. Anti-SARS-CoV-2 IgG were assed using chemiluminescence immunoassay technology and all samples with a positive or equivocal test result were re-tested with two additional serological tests. Findings1538 students and 507 teachers participated in this study. The seropraevalence for SARS-CoV-2 was 0.6%. Even in schools with reported Covid-19 cases before the Lockdown of March 13th no clusters could be identified. 23/24 participants with a household history of COVID-91 were seronegative. By using a combination of three different immunoassays we could exclude 16 participants with a positive or equivocal results after initial testing. InterpretationStudents and teachers do not play a crucial role in driving the SARS-CoV-2 pandemic in a low prevalence setting. Transmission in families occurs very infrequently, and the number of unreported cases is low in this age group, making school closures not appear appropriate as a strategy in this low prevalence settings. FundingThis study was supported by a grant from the state of Saxony
