While COVID-19 vaccines were designed primarily to prevent severe forms of the disease, recent studies reveal an unexpected effect that has sparked curiosity in the scientific world: a potentially beneficial impact on certain cancers , particularly in patients undergoing immunotherapy.

Promising results observed in cancer patients

According to several studies conducted in the United States and Europe, people with cancer who received an mRNA vaccine (Pfizer-BioNTech or Moderna) have better immune responses and, in some cases, prolonged survival when they receive immunotherapy treatment at the same time.

A study conducted by researchers at MD Anderson Cancer Center and the University of Florida showed that patients with melanoma or non-small cell lung cancer who were vaccinated within 100 days of starting immune checkpoint inhibitor therapy had a median survival rate nearly double that of unvaccinated patients.

Although this work is still at an observational stage, the researchers speak of a "robust" signal that merits further investigation.

An intriguing immune “boost”

The hypothesis put forward by the scientific community is based on the role of the messenger RNA vaccine in stimulating innate and adaptive immunity .

In other words, the injection doesn't just prepare the body to recognize the SARS-CoV-2 virus: it could also awaken certain immune cells , making tumors more detectable by anticancer treatments.

"Messenger RNA vaccines appear to act as a true catalyst for the immune system. This reaction could amplify the effectiveness of existing immunotherapies," explains an immuno-oncologist quoted by Nature Reviews Immunology .

A discovery that gives rise to hope, but needs to be confirmed

Researchers urge caution, however. The available studies are mostly retrospective and therefore subject to bias. It is possible, for example, that vaccinated patients already benefit from better medical monitoring or a more favorable general condition.

Prospective clinical trials are currently being considered to verify these observations and determine the extent to which vaccination could be integrated into certain cancer treatment strategies.

Not a vaccine against cancer, but a path for the future

Experts insist: this is not a "cancer vaccine."

The observed effect is a positive side effect , that is, an unexpected but beneficial consequence.

If these results are confirmed, they could open the way to new therapeutic approaches combining RNA vaccines and immunotherapy , already considered one of the medical revolutions of the 21st century.