key: cord-0840036-h8qb41k7 authors: Häusler, Martin; van Helden, Josef; Kleines, Michael title: Retarded decline of the share of SARS‐CoV‐2‐positive children in North Rhine‐Westphalia, Germany date: 2020-09-28 journal: J Med Virol DOI: 10.1002/jmv.26564 sha: e1c35422d88d5d98a216c27d53d8f53496f8d5cf doc_id: 840036 cord_uid: h8qb41k7 Knowledge on the mechanisms of viral spread, of time‐related changes and age‐specific factors of SARS‐CoV‐2 infections is important to develop recommendations aimed at controlling the pandemic. In this context, longitudinal data on proportions of positive results in different age groups are rare. Data on total positive counts and on shares of positive counts deriving from a private (MVZ) and a University (RWTH) laboratory were analyzed retrospectively and compared with public data on total positive counts of the Robert Koch Institute (RKI). Data covered weeks 9 to 24 of the year 2020 and all patient ages. Total positive counts were lower in children compared to adults. Proportions of children and adults tested positive were 3‐5% and 5‐7%, respectively. RKI and MVZ data showed similar time‐related patterns. Patients of 20 to 60 years of age did account for the initial virus spread (maximum infection rates at weeks 9‐11). Thereafter infection rates decreased in older patients whereas children did not show a comparable time‐related decrease. Pediatric data generated in outpatient settings and hospitals differed markedly which should be considered in further studies. In summary, compared with adults children are less affected by SARS‐CoV‐2 infections and are unlikely to account for the initial viral spread. However, children show sustained viral activity and may serve as a viral reservoir. This article is protected by copyright. All rights reserved. Children play a particular role in the concepts aiming at controlling SARS-CoV-2 infections. They are less affected clinically than adults regarding numbers of infected This article is protected by copyright. All rights reserved. individuals and disease severity. Prevention concepts are more difficult to enforce: the younger, the less they will tolerate masks or respect physical distancing; the most important tools to prevent SARS-CoV-2 transmission. Similar to adults, typical symptoms in children are fever, respiratory problems, and, less frequently, enteritis. Children may show prolonged respiratory and fecal viral shedding as viral RNA has been detected for more than 4 weeks in respiratory and stool specimens [1] [2] [3] [4] [5] [6] [7] . Transmission of SARS-CoV-2 by children, however, has been reported to be considerably less frequent than by adults and most pediatric infections could so far be attributed to intrafamilial transmission [8] [9] [10] [11] . These data determine pediatric infection control recommendations including controversely discussed decisions on closure of schools and nurseries [12] [13] [14] [15] . These data were compared to data from the German nationwide infection surveillance of the Robert Koch Institute (RKI) (188133 data sets), a federal office, providing data on the number of patients infected with SARS-CoV-2 throughout Germany which derive from public health offices of all counties. These data are publicly accessible via the "surfstat" database (https://survstat.rki.de) and crucial for decisions of the German government aimed at controlling the COVID-19 pandemic. This article is protected by copyright. All rights reserved. Data obtained from the MVZ and RWTH laboratories and the RKI database comprised age at diagnose, SARS-CoV-2 PCR result from different respiratory specimens and week at investigation. MVZ data further differentiated between the source of the specimen (hospital versus not hospital) and included the postal codes of the patients. Data sets did comprise analyses performed between February 24 th and June 6 th , e.g. the weeks 9 to 24 of the year 2020. To further study the number of patients tested positive at different ages data were further analyzed focusing on 5-year age groups which mirrors the RKI data ( Figure 1c ). According to MVZ data, absolute numbers of SARS-CoV-2 positive adults peak This article is protected by copyright. All rights reserved. To study to which extent regional data from North Rhine-Westphalia might mirror the nationwide RKI data the following method of data normalization was applied: At first the absolute number of patients tested positive during weeks 9 to 24 was calculated This article is protected by copyright. All rights reserved. Data from both sources showed a similar distribution pattern indicating a good agreement: an initial increase of absolute positive results was followed by a marked decrease among adults and older children. No comparable decrease was observed for children below 15 years of age. Proportions of adults tested positive for SARS-CoV-2 peak earlier than of children between 5 and 14 years of age. To evaluate whether the retarded decline of children positive for SARS-CoV-2 observed in figure 2b is still visible when analyzing shares of positive tests, we used percentages of positive test results from MVZ data on 5-year age groups and again applied the above described method of normalization ( Figure 3a ). Younger adults and adolescents (age 15 to 44 years) were found to show maximum positivity rates at week 9. They were followed by older adults (age from 45 years) who mostly peaked in week 11. Children of 5-14 years peaked later namely at weeks 13 and 16, respectively. This indicates that adolescents and younger adults might first have been affected by the pandemic. These findings were specified by refocusing on 1-year age groups. For every 1-year age group the week with the highest share of positive tests was determined. Afterwards the respective week was plotted against the respective one-year age group. This resulted in three clusters (figure 3b): Adults between 20 and 60 years of age (cluster 1) were affected early during the pandemic (weeks 9 to 11), followed by older persons (cluster 2; weeks 11 to 15). Children below 15 years of age were the latest to show highest infection rates (up to week 19; cluster 3). The major process underlying this delayed peak of infection was constant low-level infectious activity. This is depicted in figure 3c showing the cumulative weekly changes of infection rates in This article is protected by copyright. All rights reserved. Hospital (513 of 10187 positive; 5%). Hereby the above mentioned method of data normalization was applied again. As for adults similar patterns were observed for all three settings (Fig. 4a ). Data from children tested in ambulatory settings showed a similar pattern as known from the overall analysis (Figure 4b ). Children tested in hospitals, in contrast, only rarely tested positive which confirms that SARS-CoV-2 -2 infections are less severe in children and that pediatric data generated in hospitals might not mirror the true epidemiological situation. This is one of the rare studies providing data on serial investigations on SARS-CoV-2 in respiratory specimens, also including proportions of patients tested positive in different age groups. The findings on total numbers of SARS-CoV-2 positive patients corroborate data of the nationwide German SARS-CoV-2 database of the RKI which confirms that MVZ data can be used to analyze the situation in Germany (figures 2a + This article is protected by copyright. All rights reserved. Accepted Article b). As RKI data do not include general testing rates, the MVZ data additionally facilitate interpretation of RKI data. For example, children were tested less frequently which limits knowledge of the pandemic in this patient group (figure 1b). As the MVZ data contain data of the Heinsberg region, the first German region that experienced a SARS-CoV-2 -related lock down from week 9, these data also include the early phase of the pandemic in Germany. Studying these age-and time-related data it was found that first infection peaks This article is protected by copyright. All rights reserved. Dynamic viral SARS-CoV-2 RNA shedding in in children: preliminary data and clinical consideration of Italian regional center A Well Infant with Coronavirus Disease 2019 (COVID-19) with High Viral Load. 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