A recent study published in the journal Nature has found that COVID-19 mRNA-based vaccines may have a surprising benefit: helping the immune system fight cancer. Researchers discovered that mRNA can train the immune system to kill tumors, even if the mRNA is not related to cancer. This finding led to an investigation into whether COVID-19 mRNA vaccines could have antitumor effects.

The study analyzed clinical outcomes for over 1,000 late-stage melanoma and lung cancer patients treated with immune checkpoint inhibitors, a common approach to train the immune system to kill cancer. Patients who received either the Pfizer or Moderna mRNA-based COVID-19 vaccine within 100 days of starting immunotherapy were more than twice as likely to be alive after three years compared to those who didn’t receive either vaccine.

The research also found that patients with tumors that don’t typically respond well to immunotherapy saw a nearly fivefold improvement in three-year overall survival. The link between improved survival and receiving a COVID-19 mRNA vaccine remained strong even after controlling for factors like disease severity and co-occurring conditions.

To understand the underlying mechanism, researchers used animal models and found that COVID-19 mRNA vaccines act like an alarm, triggering the body’s immune system to recognize and kill tumor cells. When combined with immune checkpoint inhibitors, the vaccines coordinate to unleash the full power of the immune system to kill cancer cells.

This discovery is significant because immunotherapy with immune checkpoint inhibitors has revolutionized cancer treatment over the past decade, but these therapies are often ineffective in patients with “cold” tumors that evade immune detection. The findings suggest that mRNA vaccines may provide the spark the immune system needs to turn these “cold” tumors “hot.”

Researchers are now preparing to test this treatment strategy in a nationwide clinical trial in patients with lung cancer. The study will determine whether COVID-19 mRNA vaccines should be included as part of the standard of care for patients receiving an immune checkpoint inhibitor. If successful, this approach could help extend the benefits of immunotherapy to millions of patients who currently lack effective treatment options.