Severe COVID infections could help reduce the size of cancerous tumours, a new groundbreaking study has found.

The research, published in the Journal of Clinical Investigation, has revealed there could be an upside to severe COVID infections.

While this revelation comes from research on mice, it could have implications for future cancer therapies but experts are warning this is no reason to go out seeking COVID.

The study looked at monocytes, a type of white blood cell that’s pivotal in fending off infections and other threats. In cancer patients, these cells can be used by tumors to shield the cancer from immune attacks.

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But researchers found that a serious bout of COVID prompts the body to churn out a special breed of monocyte that still can attack the cancer. These “induced” monocytes, while primed to go after the virus, can also deal with the cancer.

The secret seems to lie in the genetic code of coronavirus. The study reveals that these unique monocytes come equipped with a receptor that latches onto a particular sequence of COVID RNA.

Ankit Bharat, a scientist at Northwestern University in Chicago, explained: “If the monocyte was a lock, and the COVID RNA was a key, then COVID RNA is the perfect fit.”

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The study involved mice with stage 4 cancers of the skin, lungs, breast, and colon. The team treated these mice with a drug that simulated a severe immune reaction to COVID, triggering the production of a specialized kind of monocyte. It caused the tumors to significantly reduce in size for all the cancer types examined.

These unique monocytes maintained their anti-cancer functions, unlike typical monocytes which can be hijacked by tumors to serve as guardian cells. These special monocytes traveled to the tumor’s location, which is usually beyond the reach of most immune cells, and there they activated natural killer cells to target the cancer cells, leading to tumor reduction.

Immunotherapy has been a beacon of hope, yet its effectiveness is limited as it only benefits about 20 to 40 per cent of patients, often due to the body’s insufficient T cell production. This over-reliance on T cells is seen as a significant constraint in current immunotherapy strategies.

Although just tested on mice so far, if this new mechanism can be adapted to human physiology and possibly other cancer types, the potential is vast.

COVID-19 vaccines likely won’t activate this newly discovered process since they don’t use the virus’s complete RNA sequence. But the findings could inspire the design of innovative drugs and vaccines capable of invoking these tumor-fighting monocytes.