Childhood cancer survivors face higher risk of Covid-19 severity

According to a comprehensive study in Denmark and Sweden, adults with surviving childhood cancer face a risk of severe Covid-19 complications, even in the decades after the original diagnosis.

The study shows that while these survivors are unlikely to sign up for Covid-19 initially, their results are significantly worse when infection occurs.

The findings challenge hypotheses about the health of long-term cancer survivors and highlight how childhood treatments create lasting vulnerability. Despite higher vaccination rates than the general population, childhood cancer survivors still need to be hospitalized, intensive care or die from Covid-19 at a high speed company.

Decades of health effects

“It is important to understand that even if these people are not often infected, the consequences can be even worse,” stressed Javier Louro, a postdoctoral researcher at the Karolinska Institute and lead author of the study.

The study, published in Europe, tracked survivors for three years from January 2020 to December 2022. The study population included people diagnosed with cancer at the beginning of the pandemic, at least 20 years old, with an average age of about 41 years.

The researchers compared survivors with randomly selected individuals from the general population and their siblings, providing a strong control group that constitutes population-wide and family-specific factors.

The pandemic reveals vulnerability

Risks become particularly evident during widespread viral transmission. The initial differences were subtle, but with the emergence of new variants such as Alpha and Omicron, the gap in severe outcomes significantly widened between the survivors and the comparison group.

The main findings of the study include:

• Survivors aged 50 or older showed serious shared age 19 at 85% higher risk
• Those diagnosed with cancer at age 15 or older are at more than twice the risk
• Compared with the general population, solid tumor survivors have a 63% higher risk
• Starting from July 2021, the risk difference is most obvious, with survivors showing 2.35 times the risk of severe COVID

National differences reveal policy implications

Comparison of Denmark and Sweden provides unique insights on how pandemic management strategies affect vulnerable groups. Sweden’s looser approach (relying on advice rather than authorization) continues to have a higher risk ratio to survivors than Denmark’s stricter early restrictions.

However, the two countries eventually reached similar cumulative rates of severe Covid-19 among survivors at the end of the study, suggesting that pandemic control measures may have affected timing, not overall impact.

The study utilizes the integrated health registry of Nordic countries, which captured almost population data with minimal losses. This registry-based approach eliminates common biases associated with self-reported data or selective participation.

Clinical impact on future preparation

“Our results suggest that childhood cancer survivors should be considered as risk groups for future pandemics or other health crises,” Louro noted. “This may involve prioritizing vaccination or providing special protection during high transmission.”

These findings range beyond Covid-19 and have had an impact on seasonal flu and other infectious diseases. The study authors highlighted the persistent vulnerability of cancer treatment for many years, suggesting that survivors’ immune systems may be damaged for a long time.

It is worth noting that survivors actually showed more cautious behavior during the pandemic, and although they were vulnerable to severe outcomes when infected, the overall infection rate was lower. This suggests that risk awareness and protective behaviors may help limit the scope of exposure.

The study is now more than 85% in high-income countries as the number of childhood cancer survivors continues to grow, with the five-year survival rate in high-income countries now exceeding 85%. This growing survivor population is an important consideration for public health planning and emergency preparedness.

The study, supported by the Danish and Swedish Children’s Cancer Foundations and Research Council, reflects a Nordic cooperative approach to understanding the long-term health of cancer survivors.

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