The innovative messenger RNA (mRNA) vaccines that thwarted the ravages of COVID-19 may also help fight tumors in cancer patients, according to a new analysis of medical records and studies in mice.

People with cancer who coincidentally received the mRNA shots before starting drugs designed to unleash the immune system against tumors lived significantly longer than those who didn’t get vaccinated, a research team announced yesterday at the European Society for Medical Oncology Congress in Berlin. Laboratory experiments by the group suggest the vaccines rev up the immune system, making even stubborn tumors more susceptible to treatment.

The findings underscore the still-untapped potential of mRNA technology at a time when President Donald Trump’s administration has backed away from funding the area. “I think this data is extraordinary,” says Ryan Sullivan, an oncologist and immunologist at Massachusetts General Hospital who wasn’t involved in the new research. Although the analysis of cancer patient data was retrospective, he notes that the observed association between COVID-19 vaccination and improved survival “is very strong.”