Backround Post-COVID19 complications such as pediatric inflammatory multisystem syndrome (PIMS) and Long-COVID19 move increasingly into focus, potentially causing more harm in this age group than the acute infection. To better understand the symptoms of long-COVID19 in adolescents and to distinguish infection-associated symptoms from pandemic-associated symptoms, we conducted a Long-COVID19 survey, comparing responses from seropositive and seronegative adolescents. To our knowledge, data of Long-COVID19 surveys with seronegative control groups have not been published yet. Methods Since May 2020 students grade 8-12 in fourteen secondary schools in Eastern Saxony were enrolled in the SchoolCovid19 study. Seroprevalence was assessed via serial SARS-CoV-2 antibody testing in all participants. Furthermore, during the March/April 2021 study visit all participants were asked to complete a 12 question Long-COVID19 survey regarding the occurrence and frequency of difficulties concentrating, memory loss, listlessness, headache, abdominal pain, myalgia/ arthralgia, fatigue, insomnia and mood (sadness, anger, happiness and tenseness). Findings 1560 students with a median age of 15 years participated in this study. 1365 (88%) were seronegative, 188 (12%) were seropositive. Each symptom was present in at least 35% of the students within the last seven days before the survey. However, there was no statistical difference comparing the reported symptoms between seropositive students and seronegative students. Whether the infection was known or unknown to the participant did not influence the prevalence of symptoms. Interpretation The lack of differences comparing the reported symptoms between seropositive and seronegative students suggests that Long-COVID19 might be less common than previously thought and emphasizing the impact of pandemic-associated symptoms regarding the well-being and mental health of young adolescents. Funding This study was supported by a grant by the Federal State of Saxony. M.K.W. was supported by the Else Kroener-Fresenius Center for Digital Health (EKFZ), TU Dresden, Germany.