Statement of the Ad Hoc Commission SARS-CoV-2 of Society of Virology: SARS-CoV-2 prevention measures at the start of school after the summer holidays, 06.08.2020
06/08/2020
Statement of the Ad Hoc Commission SARS-CoV-2 of Society of Virology: SARS-CoV-2 prevention measures at the start of school after the summer holidays, 06.08.2020
In recent weeks, there has been an increase in new infections with SARS-CoV-2. As the holidays are about to end or have just ended in some federal states, there are increasing concerns about the decision to open schools. According to current knowledge, infections with SARS-CoV-2 in children are in the vast majority mild, with significantly lower rates of hospitalisation, complications and deaths than in adults.
We are in favour of any measure that serves the purpose of keeping schools and educational institutions open in the coming winter season. Not only the relief for working parents, but also the well-being of the children are indispensably linked to a functioning school operation. However, school operations must be linked to pragmatic concepts that can eliminate or at least significantly reduce the risk of infection spreading in schools. For effective suppression of the spread of the virus in society as a whole, it remains a basic requirement to keep virus circulation in schools low. At the same time, effective control of new infections in the school environment, i.e. the private environment of pupils and teachers, is the best prevention of the virus entering schools.
We caution against the notion that children play no role in the pandemic and in transmission. Such notions are not in line with scientific evidence. Lack of prevention and control measures could lead to outbreaks in a short time, which would then force renewed school closures. Underestimating transmission risks in schools would be counterproductive to child well-being and economic recovery.
Infection rates in children and their role in the pandemic have so far only been incompletely recorded by scientific studies. Recent scientific publications and concrete observations in some countries indicate that the minimal role of children, which was initially assumed in some cases, must be called into question. The majority of early studies were conducted under the (exceptional) conditions of far-reaching contact-reducing regulations (so-called "lockdown") with school closures or during the period of low baseline incidence immediately after the lockdown in Germany. As a basis for decision-making, they are therefore only of limited informative value for the situation to be expected in Germany in the near future. Under certain circumstances, children may account for a non-negligible proportion of SARS-CoV-2 infections. In the meantime, the percentage of children in the total number of new infections in Germany is of a magnitude that corresponds to the proportion of children in the total population.1
The known incidence of SARS-CoV-2 infection only indicates the actual incidence of infection in the population with a delay. Control measures against a dynamic incidence of infection are generally subject to latency. We therefore tend to take a cautious approach when interpreting the scientific data. Cases in children may have been overlooked in the initial phase of the epidemic, as testing was primarily carried out for symptoms and the symptoms in children are generally less pronounced. In the meantime, it has been shown that the viral load in children does not differ (or not to a clinically relevant extent) from the viral load in adults in terms of detectable RNA concentrations in swabs.2-5 Evidence of the significance of viral load measurement for the detection of actually infectious viral material is now available.6-8 The interpretation of data on the actual frequency of transmission in children compared to adults remains difficult. Results from some carefully conducted household studies showed that children were infected at about the same rate as adults.9,10 The frequency of transmission from children remains unclear. A new comprehensive observational study from Italy suggests that children are more likely to be infected, which the authors attribute to their more intensive contact behavior.11 A study by Zhang et al. was able to show that children, despite higher assumed contact rates, had about the same frequency of infection as adults, from which a lower susceptibility of children was inferred.10 A modeling study from Israel uses statistical reconstructions of probable transmission patterns to estimate that children are about half as susceptible to infection as adults.12 While these studies are based on household observations, however, there is little data from the actual school situation. In a more recent study from South Korea, a transmission frequency comparable to that of adults was demonstrated for pupils in the secondary school age range (10-19 years), even if there were usually only mild or no symptoms.13 A study from Australia examined 12 children and 15 adults who had each attended school and daycare during their infectious phase (counted from day 2 before the onset of symptoms). In 633 contact persons tested in the laboratory, 18 subsequent transmissions were found. This number should not be considered low, because when each individual primary case became known, an immediate home quarantine of the entire class/group association and an immediate closure of the entire facility for approximately two days took place, and the schools were only in attendance for half of the study period anyway.14
Examples of actual SARS-CoV-2 clusters in schools in Israel and Australia underline the given risk of outbreaks in the education sector, especially with an increased overall incidence of infection in the population.15,16
One of the important new findings on SARS-CoV-2 that must be taken into account when opening schools concerns the now recognized possibility of aerosol transmission, i.e. transmission through the air, especially indoors with insufficient air circulation17. The more people there are in a closed room and the longer the time spent there, the greater the risk of transmission.
In relation to the opening of schools in autumn, this means that additional measures should be taken to minimise transmission risks in schools. This includes, for example, reducing class sizes depending on the number of new infections, making full use of spatial resources and finding pragmatic solutions for improved air exchange in public buildings such as schools. The implementation of technical measures to ensure sufficient indoor air exchange is not within the competence of infection sciences. For this, the involvement of technical expertise is urgently needed.
From a virological point of view, fixed small groups including teaching staff should be defined with as little mixing of the groups as possible during the school day. Lesson units could be distributed as widely as possible per small group over different times of the day and days of the week. Digital solutions with a mix of face-to-face teaching and homework units could offer further possibilities to relieve spatial capacities.
If there is a critical increase in new infections towards the end of the year with regular involvement of educational institutions, an extension of the Christmas holidays should be discussed in order to reduce the periods with the highest infection activity. In particular, an extension into the new year seems sensible, especially because there may presumably be a further increase in infection risks over Christmas due to holiday-related travel and family celebrations.
The evidence on the protective effect of consistent and correct use of everyday masks has increased in the meantime.18, 19 In view of the real risk of transmission between pupils who do not (yet) have any symptoms of illness at the time of infection, we therefore advocate the consistent wearing of everyday masks in all school years, including during lessons, from a virological point of view alone. This should be accompanied by an age-appropriate introduction of the children to the necessity and scope of preventive measures. Of course, consistent hand hygiene should be maintained, even if surface transmission was probably initially overestimated and airborne transmission underestimated. The recommendations from the first half of the year should be followed up here. Measures in the areas of droplet, aerosol and contact transmission are not interchangeable.
Pupils with an acute respiratory tract infection should be examined by laboratory diagnostics even if they have mild symptoms, if this is possible, because they play an indispensable role in the early detection of school outbreaks as indicators of transmission foci (clusters). Until the test result is available, they should stay away from school. A laboratory diagnostic clarification could be carried out by doctors in private practice or specially set up testing centres. A particularly low-threshold testing should be ensured for teaching staff. The organisational goal for the testing of pupils and especially teaching staff should be the transmission of results within 24 hours after taking the sample.
Students and teachers who test positive are indicator cases for transmission clusters. A general and immediate short-term quarantine could be considered for the treatment of transmission clusters. Immediate isolation of clusters has proven successful in Japan in containing the first wave.20,21 It is also provided for by the recommendations of the RKI, but implementation in practice is often delayed by the desire for preliminary diagnostic clarification of the extent of cluster transmission. To prevent major school outbreaks, however, an immediate quarantine of the entire social group, at least for a short time, is necessary. At the end of a short-term quarantine, the members of the cluster could be "tested free", i.e. a further quarantine would then no longer be necessary. It is important to create continuous, non-overlapping social groups (usually class groups) within the school. The need for a short quarantine if an infection is detected in a class group should be known throughout the school and implemented by the respective school management in immediate coordination with the responsible health authority.
Authors and members of the Ad-hoc Commission SARS-CoV-2 (in alphabetical order):
Prof. Ralf Bartenschlager
Molecular Virology
Heidelberg University Hospital
Prof. Stephan Becker
Institute for Virology
University of Marburg
Prof. Melanie Brinkmann
TU Braunschweig
Helmholtz Centre for Infection Braunschweig
Brunswick
Prof. Jonas Schmidt-Chanasit
Bernhard Nocht Institute for Tropical Medicine, Hamburg
Prof. Sandra Ciesek
Institute for Medical Virology
Frankfurt University Hospital
Prof. Christian Drosten
Institute for Virology,
Charité University Medicine Berlin
Prof. Isabella Eckerle
Centre for Emerging Viral Diseases
University Hospital Geneva, Switzerland
Prof. Marcus Panning
Institute for Virology
Freiburg University Hospital
Prof. Stephanie Pfänder
Department of Molecular and Medical Virology
Ruhr University Bochum
Prof. John Ziebuhr
Medical virology
University of Giessen
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