COVID-19 and flu may reactivate dormant cancer cells, study finds

Corona and flu infections may play a role in the recurrence of cancer in previously recovered patients. The viruses have been shown, at least in mice, to be able to reactivate "dormant" breast cancer cells that have settled in the lungs, international researchers report in Nature.

UMC Utrecht professor Roel Vermeulen participated in the research. He found indications in British data that people who had previously recovered from cancer faced a higher risk of the disease returning after a COVID-19 infection. He plans to conduct follow-up research on this, funded by KWF Kankerbestrijding.

Vermeulen specifically examined cancer-related deaths among people who had been diagnosed five to ten years earlier and contracted the new virus during the first year of the pandemic, before vaccinations began. After the COVID-19 infection, their risk of dying from cancer was found to be three times higher.

The researchers focused on breast cancer cells, which are known to sometimes spread in small numbers to other parts of the patient’s body. This doesn’t necessarily lead to disease, but it can.

“Dormant cancer cells are like the smoldering remains of an abandoned campfire, and respiratory viruses are like a strong wind that rekindles the flames,” explained American lead researcher James DeGregori metaphorically in a statement. He suspects that the discovered mechanism may also apply to other types of cancer.

Follow-up research aims to clarify whether, and to what extent, vaccination can reduce the risks. The researchers suspect it can, as vaccination helps protect against immune system disruption caused by infections.