Abstract
An analysis of 630 hospitals and 488 COVID-19 clusters in Tokyo (2020/07-2022/05) found contrasting associations between hospital size and cluster frequency. Compared to larger hospitals (≥600 beds), smaller ones (20-99 beds) reported fewer clusters per facility (0.5 vs 2.0), but a higher cluster number per 1000 beds (6.0 vs 2.5).