A study has found that receiving an mRNA COVID-19 vaccine within 100 days of starting immune checkpoint therapy is associated with significantly longer survival in patients with advanced lung and skin cancers, Medical Xpress reports.

The analysis included data from 180 patients with stage III–IV lung cancer and 43 patients with metastatic melanoma who were undergoing immunotherapy.

Patients who received an mRNA COVID-19 vaccine within 100 days before or after beginning therapy had a median survival of about 37.3 months compared with 20.6 months for lung cancer, and 30–40 months versus 26.7 months for melanoma.

The authors highlight that the vaccine was not targeted at a tumor protein or specific antigen, yet the mRNA vaccine acted as a stimulus for the immune system — a kind of “danger signal” that mobilized immune cells against cancer cells. In preclinical mouse models, the combination of an mRNA vaccine and immunotherapy turned previously unresponsive tumors into ones that became susceptible to treatment.

Researchers caution that the findings are retrospective and still need to be validated in randomized clinical trials. Nevertheless, the results provide a strong indication of the potential of mRNA vaccines not only against infections but also as an adjunct to cancer therapy.