# The impact of the SARS-CoV-2 pandemic on umbilical cord blood transplantation in Japan: insights from an interrupted time series analysis

## TL;DR

The SARS-CoV-2 pandemic increased cord blood transplants in Japan while bone marrow transplants decreased, helping maintain overall transplant activity.

## Contribution

This study provides novel insights into how CBT became a critical alternative during the pandemic in Japan.

## Key findings

- CBT cases increased significantly by 11.06 per month during the pandemic.
- Bone marrow transplantation cases decreased by 10.74 per month during the pandemic.
- Total HSCT cases remained stable despite the pandemic disruptions.

## Abstract

The SARS-CoV-2 pandemic disrupted healthcare systems worldwide, particularly affecting hematopoietic stem cell transplantation (HSCT) activities. Understanding the impact of the SARS-CoV-2 pandemic on transplant practices, especially in Japan, where cord blood transplantation (CBT) is prevalent, is crucial. A total of 40,444 allogeneic HSCT cases in Japan between 2011 and 2021 were examined using an interrupted time series analysis to assess the impact of COVID-19 on CBT utilization. Following the SARS-CoV-2 pandemic, CBT cases demonstrated a significant increase (11.06 [95% confidence interval (CI): 1.87 to 20.25] cases per month), whereas bone marrow transplantation cases decreased, by 10.74 cases per month (95% CI, −19.84 to −1.63 cases per month). Total HSCT cases remained stable with a level change of 5.47 cases per month (95% CI, −10.07 to 21.01 cases per month) and a trend change of −1.11 cases per month (95% CI, −2.22 to 0.004 cases per month). The interrupted time series analysis showed significantly increased CBT cases in Japan, highlighting its crucial role as an alternative transplant source during the pandemic. CBT offset the impact of the decrease in bone marrow transplantation and contributed to the maintenance of HSCT activity in Japan during the unprecedented crisis.