No male predominance was found below 15 years and above 75 years of age. To evaluate whether distinct antibody subtypes were predominant in distinct age groups positive rates for IgAtype, IgGtype, and total antibodies were plotted against different 5year age groups and compared with the number of checks performed in these age groups. phase, even though waves were not primarily initiated by children. The waves’ kinetics differed actually in nearby towns. Low PCRpositive rates were limited to areas of lower human population Benidipine hydrochloride density. PCRpositive rates were higher among middleaged males compared with ladies and among very old females compared with males. From Week 25, seroprevalence rates slowly increased to 50%, indicating ongoing disease activity. In conclusion, the SARSCoV2 pandemics is definitely characterized by many local but interacting epidemics, initiated and driven by different sociable organizations. Children may not be the main initiators of disease spreading but older children may significantly affect the course of the pandemic. Large human population density is associated with higher SARSCoV2 incidence. Keywords:children, epidemiology, gender, polymerase chain reaction, human population denseness, SARSCoV2, SARSCoV2 antibodies == 1. Intro == The effect of children for the course of the pandemic is still a matter of conversation.1,2This concerns the general susceptibility of children towards severe acute respiratory syndrome coronavirus 2 (SARSCoV2),3their impact on viral transmission,3,4,5the viral loads in pediatric respiratory specimen compared with adults,6,7,8,9,10,11and the time spans of viral shedding compared with adults9,12or within different pediatric age groups.13Hereby, during the 1st phase of the pandemic, transmission rates from children to further contact persons have been reported to range from 0.5% to 20%.5,14 Although longitudinal epidemiological data are important to understand the course of the SARSCoV2 pandemic, only few studies possess provided longitudinal data spanning a longer period of time. Mensah et al.15reported on SARSCoV2 infection rates among English school children between July and December 2020, based on polymerase chain reaction (PCR) data. They found an increase of overall positive rates with age. Although low in summer, illness rates improved from August, before school reopening. Young adults were affected earlier than younger children. Despite keeping universities open during the English national lockdown in November 2020, illness rates decreased in schoolage children so that universities is probably not responsible for traveling the pandemic. Leeb et al.16described pediatric SARSCoV2 incidence rates in the United States as verified by PCR screening. Higher incidences were found among adolescents of 1217 years compared with 5 to 11yearoldchildren. From March 2020 to July 2020, incidences increased continuously, followed by a plateau in August and a decrease in September 2020.16Lim et al.17studied seroprevalence rates in different regions of the United States between March and August 2020, showing noticeable time and regionspecific differences. As antibody titers decreased over time, they suggested that seroprevalence estimations might underestimate the true cumulative incidence of SARSCoV2 infections.17Based about longitudinal antibody studies performed between January 2020 and February 2021 among German children between 1 and 10 years, Hippich et al.18reported on positive rates of up to 8%, which was higher than during PCR studies and explained by frequently asymptomatic pediatric infections. Based on serological studies from children below 18 years of age in Missisippi (USA), Hobbs et al.19calculated a continuous boost of seroprevalence rates between April and September 2020 to about 18% with no difference between boys and girls. People of color,20,21,22,23,24people with low socioeconomic status,22,23,24,25families with many members,26middleaged males,27and people from areas with higher human population densities28,29seem to have higher illness rates. A low socioeconomic status25,30,31and male gender27may further become associated with a poorer prognosis. Whereas PCR studies detect acute Benidipine hydrochloride infections, antibody studies may mirror the general course of the pandemic and the effect of vaccinations. IgM and IgG antiSARSCoV2 antibodies may already become detectable within 1 week after sign onset and display an Benidipine hydrochloride increase of detection rates until Weeks 24 (IgM) or Weeks 48 (IgG), which is definitely followed by a decrease during the following weeks.32,33,34More severely affected patients seem to develop antibodies earlier.35,36Typically, IgG antiSARSCoV2 becomes positive before the disappearance of viral shedding.13,37Similar to IgM, IgAtype antibodies may become detectable before IgGtype antibodies and may decrease more rapidly.36Heterogeneous positive rates for antiSARSCoV2 antibodies have been described at related times in different countries, which may mirror local particularities of the pandemic and the use of different test systems.38As different test systems do not display identical results, simultaneous application of different test systems has been recommended to accomplish highest detection rates.33 Based on PCR data of a large private laboratory and of the University or college Hospital RWTH Aachen laboratory, we have recently shown for the first phase of the SARSCoV2 pandemic that children, although not driving spreading of the computer virus, might serve FLJ21128 as viral reservoirs, as they did not show a similar marked decline of positive rates compared with adults.39We also found that these data were representative of the situation in Germany. We now wanted to know whether differences regarding the SARSCoV2 contamination between children and adults were also present in the second phase of the pandemic focusing on an even larger cohort of patients. We.