Clinical Report: Impact of COVID-19 on Umbilical Cord Blood Transplantation in Japan

Overview

This interrupted time series study analyzed nationwide allogeneic hematopoietic stem cell transplantation (HSCT) data in Japan from 2011 to 2021, focusing on the effects of the SARS-CoV-2 pandemic on umbilical cord blood transplantation (CBT). Despite global declines in HSCT activities during the pandemic, Japan maintained stable HSCT volumes, with CBT playing a key role due to its immediate availability and cryopreserved grafts.

Background

The COVID-19 pandemic posed significant challenges to healthcare systems worldwide, particularly affecting immunocompromised patients undergoing HSCT. Risks included donor infection and reduced donor availability, leading to declines in transplantation activities globally. Japan, however, sustained HSCT procedures, potentially due to the widespread use of CBT, which offers cryopreserved stem cells readily available without SARS-CoV-2 exposure. Understanding these dynamics is crucial for optimizing transplant strategies during public health emergencies.

Data Highlights

A total of 40,444 allogeneic HSCT cases were analyzed from 2011 to 2021, with 33,170 cases before and 7,274 cases after the onset of the SARS-CoV-2 pandemic. The median patient age was 49.0 years, and 59.0% were male. Interrupted time series analyses were employed to assess monthly trends in HSCT and CBT case numbers, with sensitivity analyses including Bayesian time-series modeling to confirm robustness.

Key Findings

• Japan maintained stable allogeneic HSCT activity during the COVID-19 pandemic, contrasting with declines reported in Europe and globally.
• Umbilical cord blood transplantation (CBT) was the most widely used donor source in Japan and contributed significantly to sustaining transplant volumes.
• CBT’s cryopreserved grafts allowed immediate availability, reducing risks related to donor SARS-CoV-2 infection and logistical challenges.
• Interrupted time series analysis demonstrated no significant decrease in monthly CBT cases after the pandemic onset.
• National registry data from TRUMP 2 provided comprehensive, representative insights into transplantation trends over a decade.

Clinical Implications

The findings highlight the clinical advantage of utilizing cryopreserved umbilical cord blood as a donor source during pandemics or other emergencies, ensuring uninterrupted transplantation services. Clinicians should consider CBT as a strategic option to mitigate risks associated with donor availability and infection. Maintaining robust cord blood banks and integrating CBT into transplant protocols can enhance resilience against future healthcare disruptions.

Conclusion

Japan’s sustained HSCT activity during the COVID-19 pandemic underscores the critical role of umbilical cord blood transplantation as a reliable and readily available donor source. These insights support the strategic incorporation of CBT in transplantation programs to safeguard patient care during global health crises.

References

1. Worldwide Network for Blood and Marrow Transplantation et al. -- Impact of COVID-19 on HSCT
2. Japanese Data Center for Hematopoietic Cell Transplantation (JDCHCT) -- TRUMP 2 Registry Data
3. European Society for Blood and Marrow Transplantation (EBMT) -- HSCT Trends During COVID-19