Covid19-Sources

Antibody tests, even microneutr., might not necessarily indicate SARS-CoV-2. We need PCR tests, if possible with sequencing. In north of Paris, after combing through 124 ICU patient records, 14 selected for PCR tests, 1 positive SARS-CoV-2. So easy! 5/13 https://t.co/PNHxWjvJTi

BACKGROUND: Waning of vaccine protection against SARS-CoV-2 infection or COVID-19 disease is a concern. This study investigated persistence of BNT162b2 (Pfizer-BioNTech) vaccine effectiveness against infection and disease in Qatar, where the Beta and Delta variants have dominated incidence and PCR testing is done at a mass scale. METHODS: A matched test-negative, case-control study design was used to estimate vaccine effectiveness against SARS-CoV-2 infection and against any severe, critical, or fatal COVID-19 disease, between January 1, 2021 to August 15, 2021. RESULTS: Estimated BNT162b2 effectiveness against any infection, asymptomatic or symptomatic, was negligible for the first two weeks after the first dose, increased to 36.5% (95% CI: 33.1-39.8) in the third week after the first dose, and reached its peak at 72.1% (95% CI: 70.9-73.2) in the first five weeks after the second dose. Effectiveness declined gradually thereafter, with the decline accelerating ≥15 weeks after the second dose, reaching diminished levels of protection by the 20th week. Effectiveness against symptomatic infection was higher than against asymptomatic infection, but still waned in the same fashion. Effectiveness against any severe, critical, or fatal disease increased rapidly to 67.7% (95% CI: 59.1-74.7) by the third week after the first dose, and reached 95.4% (95% CI: 93.4-96.9) in the first five weeks after the second dose, where it persisted at about this level for six months. CONCLUSIONS: BNT162b2-induced protection against infection appears to wane rapidly after its peak right after the second dose, but it persists at a robust level against hospitalization and death for at least six months following the second dose.   ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement The authors are grateful for institutional salary support from the Biomedical Research Program and the Biostatistics, Epidemiology, and Biomathematics Research Core, both at Weill Cornell Medicine-Qatar, as well as for institutional salary support provided by the Ministry of Public Health and Hamad Medical Corporation. The authors are also grateful for the Qatar Genome Programme for institutional support for the reagents needed for the viral genome sequencing. The funders of the study had no role in study design, data collection, data analysis, data interpretation, or writing of the article. Statements made herein are solely the responsibility of the authors. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was approved by the Hamad Medical Corporation and Weill Cornell Medicine-Qatar Institutional Review Boards with waiver of informed consent. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes The dataset of this study is a property of the Qatar Ministry of Public Health that was provided to the researchers through a restricted-access agreement that prevents sharing the dataset with a third party or publicly. Future access to this dataset can be considered through a direct application for data access to Her Excellency the Minister of Public Health (https://www.moph.gov.qa/english/Pages/default.aspx). Aggregate data are available within the manuscript and its Supplementary information.

Die meisten Kinder und Jugendlichen haben eine SARS-CoV-2-Infektion gut bewältigen können. Dennoch sind einige von ihnen von den Folgen im Sinne eines Long COVID betroffen. Dieses Beschwerdebild gilt es – nicht zuletzt im Hinblick auf psychische...

National and state data on child and teen hospitalizations for COVID-19 in the United States.

Background: Reports of waning vaccine-induced immunity against COVID-19 have begun to surface. With that, the comparable long-term protection conferred by previous infection with SARS-CoV-2 remains unclear. Methods: We conducted a retrospective observational study comparing three groups: (1)SARS-CoV-2-naive individuals who received a two-dose regimen of the BioNTech/Pfizer mRNA BNT162b2 vaccine, (2)previously infected individuals who have not been vaccinated, and (3)previously infected and single dose vaccinated individuals. Three multivariate logistic regression models were applied. In all models we evaluated four outcomes: SARS-CoV-2 infection, symptomatic disease, COVID-19-related hospitalization and death. The follow-up period of June 1 to August 14, 2021, when the Delta variant was dominant in Israel. Results: SARS-CoV-2-naive vaccinees had a 13.06-fold (95% CI, 8.08 to 21.11) increased risk for breakthrough infection with the Delta variant compared to those previously infected, when the first event (infection or vaccination) occurred during January and February of 2021. The increased risk was significant (P

Clinical syndrome coronavirus disease 2019 (COVID-19) induced by severe acute respiratory syndrome coronavirus 2 is characterized by rapid spreading and high mortality worldwide. Although the pathology is not yet fully understood, hyperinflammatory response and coagulation disorders leading to congestions of microvessels are considered to be key drivers of the still-increasing death toll. Until now, physical changes of blood cells have not been considered to play a role in COVID-19 related vascular occlusion and organ damage.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus that causes coronavirus disease 2019 (COVID-19) in human beings, has caused a serious public health issue.1 Attention to pancreatic injury is lacking, which may impact patients' prognosis. In this study, we …

Objectives To systematically reivew the observational evidence of the effect of school closures and school reopenings on SARS-CoV-2 community transmission. Setting Schools (including early years settings, primary schools and secondary schools). Intervention School closures and reopenings. Outcome measure Community transmission of SARS-CoV-2 (including any measure of community infections rate, hospital admissions or mortality attributed to COVID-19). Methods On 7 January 2021, we searched PubMed, Web of Science, Scopus, CINAHL, the WHO Global COVID-19 Research Database, ERIC, the British Education Index, the Australian Education Index and Google, searching title and abstracts for terms related to SARS-CoV-2 AND terms related to schools or non-pharmaceutical interventions (NPIs). We used the Cochrane Risk of Bias In Non-randomised Studies of Interventions tool to evaluate bias. Results We identified 7474 articles, of which 40 were included, with data from 150 countries. Of these, 32 studies assessed school closures and 11 examined reopenings. There was substantial heterogeneity between school closure studies, with half of the studies at lower risk of bias reporting reduced community transmission by up to 60% and half reporting null findings. The majority (n=3 out of 4) of school reopening studies at lower risk of bias reported no associated increases in transmission. Conclusions School closure studies were at risk of confounding and collinearity from other non-pharmacological interventions implemented around the same time as school closures, and the effectiveness of closures remains uncertain. School reopenings, in areas of low transmission and with appropriate mitigation measures, were generally not accompanied by increasing community transmission. With such varied evidence on effectiveness, and the harmful effects, policymakers should take a measured approach before implementing school closures; and should look to reopen schools in times of low transmission, with appropriate mitigation measures. All data relevant to the study are included in the article or uploaded as supplemental information. All included data in this systematic review are already in the public domain.

With the recent emergence of the B.1.617.2 (Delta) variant of SARS-CoV-2 in the U.S., many states are seeing rising cases and hospitalizations after a period of steady decline. As We used the COVID-19 Simulator , an interactive online tool that utilizes a validated mathematical model, to simulate the trajectory of COVID-19 at the state level in the U.S. COVID-19 Simulator’s forecasts are updated weekly and included in the Centers for Disease Control and Prevention (CDC) ensemble model. We employed our model to analyze scenarios where the Delta variant becomes dominant in every state. The combination of high transmissibility of the Delta variant, low vaccination coverage in several regions, and more relaxed attitude towards social distancing is expected to result in as surge in COVID-19 deaths in at least 40 states. In several states – including Idaho, Maine, Montana, Nebraska, North Carolina, Oregon, Puerto Rico, Washington, and West Virginia – the projected daily deaths in 2021 could exceed the prior peak daily deaths under current social distancing behavior and vaccination rate. The number of COVID-19 deaths across the U.S. could exceed 1600 per day. Between August 1, 2021, and December 31, 2021, there could be additional 157,000 COVID-19 deaths across the U.S. Of note, our model projected approximately 20,700 COVID-19 deaths in Texas, 16,000 in California, 12,400 in Florida, 12,000 in North Carolina, and 9,300 in Georgia during this period. In contrast, the projected number of COVID-19 deaths would remain below 200 in New Jersey, Massachusetts, Connecticut, Vermont, and Rhode Island. We project COVID-19 deaths based on the current vaccination rates and social distancing behavior. Our hope is that the findings of this report serve a warning sign and people revert to wearing masks and maintain social distancing to reduce COVID-19 associated deaths in the U.S. Our projections are updated weekly by incorporating vaccination rates and social distancing measures in each state; the latest results can be found at the COVID-19 Simulator website. ### Competing Interest Statement This research is funded by the Rockefeller Foundation grant to support the work of the Society for Medical Decision Making COVID-19 Decision Modeling Initiative, and National Science Foundation awards 2035360 and 2035361. The funding agreement ensured the authors' independence in designing the study, interpreting the data, writing, and publishing the report. Drs. Chhatwal and Ayer serve as partners of Value Analytics Labs, a healthcare analytics consulting firm that provides services to pharmaceutical and diagnostic companies. ### Funding Statement This research is funded by the Rockefeller Foundation grant to support the work of the Society for Medical Decision Making COVID-19 Decision Modeling Initiative, and National Science Foundation awards 2035360 and 2035361.The funding agreement ensured the independence of authors in designing the study, interpreting the data, writing, and publishing the report. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: All data used in this study were publicly available and therefore did not require approval from an institutional review board All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Our model is available to the public at www.covid19sim.org and data can be downloaded from the website.

PDF | Purpose. Several weeks after COVID-19 infection, some children report the persistence or recurrence of functional complaints. This clinical... | Find, read and cite all the research you need on ResearchGate

Besteht wirklich so ein großer Unterschied zwischen Inzidenz 50 und 200? „Kinder unter 12 infizieren sich doch so oder so. Hauptsache die Intensivstation läuft nicht über.“ Ist das so? Eine kleine Rechnung zur Illustration: ⬇️ 1/9 #COVID19 #GrundrechenartenAmWochende

ABSTRACTBackground:StartingDecember2020,IsraelbeganamassvaccinationcampaignagainstcoronavirusadministeringthePfizerBNT162b2vaccine,whichledtoasharpcurtailingoftheoutbreak.AfteraperiodwithalmostnoSARS-CoV-2infections,aresurgentCOVID-19outbreakinitiatedmidJune2021.PossiblereasonsforthebreakthroughwerereducedvaccineeffectivenessagainsttheDeltavariant,andwaningimmunity.TheaimofthisstudywastoquantifytheextentofwaningimmunityusingIsrael'snational-database.Methods:DataonallPCRpositivetestresultsbetweenJuly11-31,2021ofIsraeliresidentswhobecamefullyvaccinatedbeforeJune2021wereusedinthisanalysis.InfectionratesandsevereCOVID-19outcomeswerecomparedbetweenindividualswhowerevaccinatedindifferenttimeperiodsusingaPoisson regression, stratifying by age group and adjustingfor possible confounding factors.Results:TheratesofbothdocumentedSARS-CoV-2infectionsandsevereCOVID-19exhibitastatisticallysignificantincreaseastimefromsecondvaccinedoseelapsed.Elderlyindividuals(60+)whoreceivedtheirseconddoseinMarch2021were1.6(CI:[1.3,2])timesmoreprotectedagainstinfectionand1.7(CI:[1.0,2.7])timesmoreprotectedagainstsevereCOVID-19comparedtothosewhoreceivedtheir second dose in January 2021. Similar resultswere found for different age groups.Conclusions:Theseresultsindicateastrongeffectofwaningimmunityinallagegroupsaftersixmonths.Quantifyingtheeffectofwaningimmunityonvaccineeffectivenessiscriticalforpolicymakersworldwidefacing the dilemma of administering booster vaccinations.

There has been an upsurge in people with diabetes during the coronavirus pandemic. Around 40% of people who recovered from COVID-19 develop diabetes.

Background SARS-CoV-2 vaccines are highly effective at preventing COVID-19-related morbidity and mortality. As no vaccine is 100% effective, breakthrough infections are expected to occur. Methods We analyzed the virological characteristics of 161 vaccine breakthrough infections in a population of 24,706 vaccinated healthcare workers (HCWs), using RT-PCR and virus culture. Results The delta variant (B.1.617.2) was identified in the majority of cases. Despite similar Ct-values, we demonstrate lower probability of infectious virus detection in respiratory samples of vaccinated HCWs with breakthrough infections compared to unvaccinated HCWs with primary SARS-CoV-2 infections. Nevertheless, infectious virus was found in 68.6% of breakthrough infections and Ct-values decreased throughout the first 3 days of illness. Conclusions We conclude that rare vaccine breakthrough infections occur, but infectious virus shedding is reduced in these cases. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement No external funding ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was approved by Radboud university medical center Committee on Research Involving Human Subjects (CMO) and the Erasmus Medical Center Medical Ethics Committee (METC). All samples were collected following routine institutional COVID-19 testing guidelines, the participants were not subject to any procedures for the purpose of this study and all data were anonymized prior to analysis. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Data are available upon request

Correspondence from The New England Journal of Medicine — Effect of Vaccination on Household Transmission of SARS-CoV-2 in England

Background Indoor aerosol transmission of SARS-CoV-2 has been widely recognized, especially in schools where children remain in close proximity and largely unvaccinated. Measures such as strategic natural ventilation and high efficiency particulate air (HEPA) filtration remain poorly implemented and mask mandates are often progressively lifted as vaccination rollout is enhanced. Methods We adapted a previously developed aerosol transmission model to study the effect of interventions (natural ventilation, face masks, HEPA filtration, and their combinations) on the concentration of virus particles in a classroom of 160 m3 containing one infectious individual. The cumulative dose of viruses absorbed by exposed occupants was calculated. Results The most effective single intervention was natural ventilation through the full opening of six windows all day during the winter (14-fold decrease in cumulative dose), followed by the universal use of surgical face masks (8-fold decrease). In the spring/summer, natural ventilation was only effective (≥ 2-fold decrease) when windows were fully open all day. In the winter, partly opening two windows all day or fully opening six windows at the end of each class was effective as well (≥ 2-fold decrease). Opening windows during yard and lunch breaks only had minimal effect (≤ 1.2-fold decrease). One HEPA filter was as effective as two windows partly open all day during the winter (2.5-fold decrease) while two filters were more effective (4-fold decrease). Combined interventions (i.e., natural ventilation, masks, and HEPA filtration) were the most effective (≥ 30-fold decrease). Combined interventions remained highly effective in the presence of a super-spreader. Conclusions Natural ventilation, face masks, and HEPA filtration are effective interventions to reduce SARS-CoV-2 aerosol transmission. These measures should be combined and complemented by additional interventions (e.g., physical distancing, hygiene, testing, contact tracing, and vaccination) to maximize benefit. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement OK was supported by the Swiss National Science Foundation (grants no 196270 and 163878). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This research did not involve human or animal subjects, and ethical approval was therefore not required All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Access to the tool and model code can be obtained from the corresponding author.

The increasing prevalence of SARS-CoV-2 variants has raised concerns regarding possible decreases in vaccine efficacy. Here, neutralizing antibody titers elicited by mRNA-based and an adenoviral vector-based vaccine against variant pseudotyped viruses were compared. BNT162b2 and mRNA-1273-elicited antibodies showed modest neutralization resistance against Beta, Delta, Delta plus and Lambda variants whereas Ad26.COV2.S-elicited antibodies from a significant fraction of vaccinated individuals were of low neutralizing titer (IC50

Nature Microbiology - Mechanisms of antibody-dependent enhancement of disease and mitigation strategies for SARS-CoV-2 vaccines and therapies are discussed.

Querdenker verbreiten seit Frühling 2020 zahllose Theorien und Prophezeiungen, welche sich beim näheren Hinsehen meist als haltlos erweisen. Bei der Aufklärung der Theorien erweisen die Faktenchecker unschätzbare Dienste. Querdenker machen es sich nun einfach, sie behaupten die Faktenchecker lügen. Diese billige Vorgehensweise funktioniert bei Prophezeiungen nicht, man kann sie nicht einfach verleugnen, sobald deren Stichtag erreicht wurde. Die Prophezeiungen der Querdenkern basieren auf ihre Theorien. Erfüllen sich die Prophezeiungen nicht, so sind auch deren Theorien indirekt widerlegt. Die einzelnen Prophezeiungen der Querdenker geistern zwar ständig durch das Internet, aber eine Aufstellung davon fand ich nicht. Und genau hier setzt dieses Dokument an. Ich hatte anfangs nur mit einer überschaubaren Liste gerechnet - die Liste ist inzwischen ein klein wenig länger geworden.

The pandemic is giving scientists a unique view of viral evolution in action

Rumors that the CDC is moving away from its original COVID PCR test because of inaccurate results just aren't true. With other PRC tests on the market that can help doctors figure out whether you have COVID or some other virus, the original PCR test is no longer needed.

Quellen: Lambda & Immune Escape (Studie aus Japan): https://t.co/gseh1yBVwm Lambda & Immune Escape (Studie aus New York): https://t.co/JnrqQ7t0YF Mutanten-Anteil in Südamerika: https://t.co/Dt5QY8MapT Spiegel-Artikel: https://t.co/7TrFh9mksZ [10/10]

Estimating excess mortality allows quantification of overall pandemic impact. For recent decades, mortality data are easily accessible for most industrialized countries, but only a few countries have continuous data available for longer periods. Since Spain, Sweden, and Switzerland were militarily neutral and not involved in combat during both world wars, these countries have monthly all-cause mortality statistics available for over 100 years with no interruptions. We show that during the COVID-19 pandemic in 2020, Spain, Sweden and Switzerland recorded the highest aggregated monthly excess mortality (17%, 9% and 14%) since the 1918 influenza pandemic (53%, 33% and 49%), when compared to respective expected values. For Sweden and Switzerland, the highest monthly spikes in 2020 almost reached those of January 1890. These findings emphasize the historical dimensions of the ongoing pandemic and support the notion of a pandemic disaster memory gap. One-Sentence Summary During the COVID-19 pandemic in 2020, Spain, Sweden, and Switzerland recorded their highest monthly excess and all-cause mortality levels since the 1918 influenza pandemic, emphasizing the historical dimension of the ongoing pandemic. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was funded by the Foundation for Research in Science and the Humanities at the University of Zurich (grant STWF-21-011, grantees K.S. and J.F.) and the Swiss National Science Foundation (SNSF project number 189498, grantee M.E.). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study re-uses publicly available and monthly aggregated mortality figures at the national level, published by the national statistical authorities. Therefore, ethics approval was not necessary in this case. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data and code used in this analysis are provided here: https://github.com/RPanczak/ISPM_excess-mortality/.

Despite a highly successful vaccination campaign in the UK, the coronavirus disease 2019 (COVID-19) pandemic is not over, and we are currently seeing rapidly rising infection rates. While there is an understandable and intense desire for ‘normality’ to return, we need to sustain our efforts to limit the transmission and impacts of the virus, particularly for the most vulnerable, for the longer term. To prepare for the winter period and beyond, the priorities over the summer period must be to: ● Maximise the speed and uptake of COVID-19 vaccination in all eligible age groups, and prepare for possible booster vaccines in priority groups and vaccination against influenza later in the year. ● Increase the ability of people with COVID-19 to self-isolate through financial and other support, with a particular focus on those in areas of persistent transmission and in the lowest socio-economic groups. ● Boost capacity in the NHS (staff and beds) to: build resilience against future outbreaks of COVID-19 and other infectious diseases, including through improving infection prevention and control (IPC), increasing vaccination and testing capacity for COVID-19 and influenza, adequately resourcing primary care, and reducing the backlog of non-COVID-19 care. ● Provide clear guidance about environmental and behavioural precautions (such as the use of face coverings, ventilation and physical distancing) that individuals and organisations can take to protect themselves and others, especially those who are most vulnerable from infection.

Although nobody doubts the existence of long COVID in children, it is still unclear to what extent children are affected. The Ciao Corona study is a longitudinal cohort investigating SARS-CoV-2 seroprevalence and clustering of cases among around 2500 children from 55 randomly selected primary and secondary schools in the canton of Zurich in Switzerland. Between June 2020 and April 2021, we completed three testing phases where we collected venous blood for serological analysis (ABCORA 2.0 test) and asked about symptoms with online questionnaires. We compared children who tested positive for SARS-CoV-2 antibodies in October/November 2020 with those who tested negative. Children who were seronegative in October/November 2020 and seroconverted or were not retested by March/April 2021 were excluded from the analysis (n=256). In March-May 2021 we assessed the presence of symptoms occurring since October 2020, lasting for at least 4 weeks, and persisting for either >4 weeks or >12 weeks. Overall, 1355 of 2503 children with a serology result in October/November 2020 and follow up questionnaire in March/April 2021 were included. Among seropositive and seronegative 6-to 16-year-old children and adolescents, 9% versus 10% reported at least one symptom beyond 4 weeks, and 4% versus 2% at least one symptom beyond 12 weeks. None of the seropositive children reported hospitalization after October 2020. Seropositive children, all with a history of pauci-symptomatic SARS-CoV-2 infection, did not report long COVID more frequently than seronegative children. This study suggests a very low prevalence of long COVID in a randomly selected population-based cohort of children followed over 6 months after serological testing. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study is part of Corona Immunitas research network, coordinated by the Swiss School of Public Health (SSPH+), and funded by fundraising of SSPH+ that includes funds of the Swiss Federal Office of Public Health and private funders (ethical guidelines for funding stated by SSPH+ will be respected), by funds of some Cantons of Switzerland and by institutional funds of the Universities. Additional funding, specific to this study is available from the University of Zurich Foundation and the Federal Office of Public Health. The funder/sponsor did not have any role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Ethics Committee of the Canton of Zurich, Switzerland (2020-01336) approved the study and parents/legal guardians provided written informed consent. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data are available on reasonable request.

Background The World Health Organization has recently recognized Long COVID, calling the international medical community to strengthen research and comprehensive care of patients with this condition. However, if Long COVID pertains to children as well is not yet clear. Methods An anonymous, online survey was developed by an organization of parents of children suffering from persisting symptoms since initial infection. Parents were asked to report signs and symptoms, physical activity and mental health issues. Only children with symptoms persisting for more than four weeks were included. Results 510 children were included (56.3% females) infected between January 2020 and January 2021. At their initial COVID-19 infection, 22 (4.3%) children were hospitalized. Overall, children had persisting COVID-19 for a mean of 8.2 months (SD 3.9). Most frequent symptoms were: Tiredness and weakness (444 patients, 87.1% of sample), Fatigue (410, 80.4%), Headache (401, 78.6%), Abdominal pain (387, 75.9%), Muscle and joint pain (309, 60.6%), Post-exertional malaise (274, 53.7%), rash (267, 52.4%). 484 (94.9%) children had had at least four symptoms. 129 (25.3%) children have suffered constant COVID-19 infection symptoms, 252 (49.4%) have had periods of apparent recovery and then symptoms returning, and 97 (19.0%) had a prolonged period of wellness followed by symptoms. Only 51 (10.0%) children have returned to previous levels of physical activity. Parents reported a significant prevalence of Neuropsychiatric symptoms. Conclusions Our study provides further evidence on Long COVID in children. Symptoms like fatigue, headache, muscle and joint pain, rashes and heart palpitations, and mental health issues like lack of concentration and short memory problems, were particularly frequent and confirm previous observations, suggesting that they may characterize this condition. A better comprehension of Long COVID is urgently needed..

Exploring potential mechanisms.

Models of COVID-19 outbreak trajectories and hospital demand