BACKGROUND: In addition to widely used basic hygiene measures in school, school closures are applied to contain SARS-CoV-2 spread, although the effect on the pandemic is unclear. We proposed a simple approach to disentangle the effect of school closures from other lockdown measures on the pandemic course based on publicly available data in Germany. METHODS: We used data on the number of SARS-CoV-2 cases from the onset of the pandemic to 14th April 2021. We compared the proportion of children (5-14 years old) in all cases prior to the lockdown measures, including school closure, to that during a ten-week lockdown in Germany. The total number of paediatric cases occurring during lockdown was compared to the number expected in absence of school closures. The latter was calculated based on the actual weekly number of all cases and the pre-lockdown proportion of paediatric cases. RESULTS: The proportion of children in all cases was 2.3 percentage points lower at the nadir than the proportion before the lockdown. The estimated total number of paediatric cases prevented by school closures was estimated at 13,246 amounting to 24% of the expected cases in absence of school closures. CONCLUSION: School closure during the winter lockdown reduced the number of expected SARS-CoV-2 cases in children in absence of school closures. The contribution of these prevented cases to the total population incidence is small. These data might provide the basis to model the effect of school closures in addition to basic hygiene measures on the course of the COVID-19 pandemic.