The COVID-19 pandemic has led to worldwide school closures, with a risk of learning loss. Sweden kept primary schools open, but it is unknown whether student and teacher absence and pandemic-related stress factors affected teaching and student progress negatively. In this study, reading assessment data from 97,073 Swedish primary school students (grades 1-3) were analysed to investigate potential learning loss. Results showed that word decoding and reading comprehension scores were not lower during the pandemic compared to before the pandemic, that students from low socio-economic backgrounds were not especially affected, and that the proportion of students with weak decoding skills did not increase during the pandemic. Study limitations are discussed. We conclude that open schools benefitted Swedish primary school students.