成人した小児がん生存者は重症COVID-19のリスクが高い(Adults who have survived childhood cancer are at increased risk of severe COVID-19)

2025-07-07

2025-07-04 カロリンスカ研究所(KI)

カロリンスカ研究所などの研究で、小児がんを克服した成人はCOVID-19の感染リスクは低いものの、感染した場合の重症化リスクが58%高いことが判明した。スウェーデンとデンマークの約13,000人を対象にした登録データ分析に基づく。免疫の長期的影響が影響している可能性があり、特に感染力の高い変異株流行時にリスクが顕著だった。研究者は、生存者をワクチン優先接種や感染対策の重点対象とすべきと提言している。

<関連情報>

デンマークとスウェーデンの小児がん生存者におけるCOVID-19感染と重症度:登録ベースのコホート研究とマッチ集団および兄弟姉妹の比較 COVID-19 infection and severity among childhood cancer survivors in Denmark and Sweden: a register-based cohort study with matched population and sibling comparisons

Javier Louro ∙ Christina-Evmorfia Kampitsi ∙ Hanna Mogensen ∙ Friederike Erdmann ∙ Karin Modig ∙ Anna Nilsson ∙ et al.
The Lancet Regional Health – Europe Published: July 4, 2025
DOI:https://doi.org/10.1016/j.lanepe.2025.101363

Summary

Background

During the COVID-19 pandemic, vulnerable groups faced a higher risk of severe COVID-19 outcomes. The effect of the pandemic on adult childhood cancer survivors is a significant public health concern but not sufficiently understood. We aimed to assess whether adult childhood cancer survivors had a higher risk of severe COVID-19 and registered COVID-19 infections compared to the general population.

Methods

This Nordic register-based cohort study included 5-year childhood cancer survivors diagnosed before age 20 years in Denmark and Sweden, two countries with very different pandemic responses. As comparisons, we randomly selected individuals from the general population, matched on year of birth, sex, and country, and identified all siblings of the survivors. All individuals at least 20 years old and alive on January 1, 2020, were followed until December 31, 2022. We plotted the cumulative hazard rates of severe COVID-19 and registered COVID-19 infection and fitted Cox proportional hazards models estimating adjusted hazard ratios (aHR) with 95% confidence intervals (95% CI).

Findings

The cohort included 13,659 cancer survivors, 58,803 matched comparisons, and 17,531 siblings. Childhood cancer survivors had a lower risk of registered COVID-19 infection (aHR = 0·91; 95% CI = 0·89–0·94) compared to their comparisons but a higher risk of severe COVID-19 (aHR = 1·58; 95% CI = 1·25–1·98). The latter was particularly evident during periods of widespread viral transmission, as reflected in differences between Denmark and Sweden.

Interpretation

These findings underscore the heightened vulnerability of childhood cancer survivors, even many years after their cancer diagnosis, and emphasize the need for closer monitoring and tailored interventions to safeguard this population during future health crises.