Understanding the impact of different social interactions is key to improving epidemic models. Here, we use extensive registry data -- including PCR test results and population-level networks -- to investigate the impact of school, family, and other social contacts on SARS-CoV-2 transmission in the Netherlands (June 2020--October 2021). We isolate and compare different contexts of potential SARS-CoV-2 transmission by matching pairs of students based on their attendance at the same or different primary school (in 2020) and secondary school (in 2021) and their geographic proximity. We then calculated the probability of temporally associated infections -- i.e. the probability of both students testing positive within a 14-day period. Our results highlight the relative importance of household and family transmission in the spread of SARS-CoV-2 compared to school settings. The probability of temporally associated infections for siblings and parent-child pairs living in the same household was 22.6--23.2\%, and 4.7--7.9\% for family members living in different household. In contrast, the probability of temporally associated infections was 0.52\% for pairs of students living nearby but not attending the same primary or secondary school, 0.66\% for pairs attending different secondary schools but having attended the same primary school, and 1.65\% for pairs attending the same secondary school. Finally, we used multilevel regression analyses to examine how individual, school, and geographic factors contribute to transmission risk. We found that the largest differences in transmission probabilities were due to unobserved individual (60\%) and school-level (34\%) factors. Only a small proportion (3\%) could be attributed to geographic proximity of students or to school size, denomination, or the median income of the school area.

翻译：理解不同社交互动的影响是改进流行病模型的关键。本研究利用广泛的注册数据——包括PCR检测结果和人群级网络——调查了学校、家庭及其他社交接触对荷兰SARS-CoV-2传播的影响（2020年6月至2021年10月）。我们通过匹配学生对（基于其是否就读于相同或不同的小学（2020年）和中学（2021年）以及地理邻近性），分离并比较了SARS-CoV-2潜在传播的不同情境。随后计算了时间关联感染的概率——即两名学生在14天内均检测出阳性的概率。研究结果凸显了与学校环境相比，家庭和家族传播在SARS-CoV-2传播中的相对重要性。同住一个家庭且互为兄弟姐妹或亲子关系的学生对，其时间关联感染概率为22.6%-23.2%；而居住在不同家庭中的家族成员，该概率为4.7%-7.9%。相比之下，居住邻近但未就读于相同小学或中学的学生对，其时间关联感染概率为0.52%；就读于不同中学但曾就读于相同小学的学生对，该概率为0.66%；而就读于相同中学的学生对，该概率为1.65%。最后，我们采用多层回归分析检验了个人、学校和地理因素对传播风险的贡献。结果表明，传播概率的最大差异源于未观测到的个人因素（60%）和学校层面因素（34%）。仅有小部分（3%）可归因于学生的地理邻近性、学校规模、宗教背景或学校所在地区收入中位数。