Undoubtedly, children in preschool are at high risk for COVID-19 as they have not been vaccinated, do not wear masks properly, and do not provide good hand hygiene. This study presents a girl who was not infected with SARS-CoV-2 as she wore a mask properly during the COVID-19 outbreak in her school. In January 2022, a child whose mother was reported to be positive for COVID-19 was found to have a positive SARS-CoV-2 test. It was reported that the positive child had been going to school for the last three days and did not wear a mask during this time. He did not have any symptoms. Due to close contact with the infected case, SARS-CoV-2 RT-qPCR (BioSpeedy SARS-CoV-2 kit, Bioeksen Inc., İstanbul, Türkiye) test was performed on all children. The school was immediately closed. All children and teachers working at the school were isolated at home for seven days. On the second and third days of the quarantine, 50% of the kindergarten (eight students and one teacher) tested positive for SARS-CoV-2 RT-qPCR. It was noted that the teacher had three doses with Comirnaty (formerly BioNTech, Pfizer) (BNT 162b2) (BioNTech, Fosun Pharma, Pfizer, NY, USA) and did not wear a mask in those days. In the five-year-old class, only the SARS-CoV-2 RT-qPCR tests of a girl who wore the mask appropriately and a boy who had a previous COVID-19 were negative. The tests of these children did not turn out to be positive until the end of the quarantine. In the COVID-19 outbreak that started in a kindergarten classroom, a five-year-old unvaccinated girl wearing her disposable mask properly was protected against COVID-19 and prevented the virus from spreading to her family.