• Posted October 24, 2025

Could COVID mRNA Vaccines Boost Effectiveness of Cancer Immunotherapy?

The mRNA technology powering some COVID vaccines may hold a surprising benefit for advanced cancer patients: a potential ability to "rev up" the immune system to better use immunotherapy medicines to attack tumors.

Preliminary research published Oct. 22 in the journal Nature found that patients with advanced lung or skin cancer who received a Pfizer or Moderna COVID shot within 100 days of starting immunotherapy lived significantly longer than those who didn't.

Researchers say the messenger RNA (mRNA) molecule in the vaccines appears to sensitize the immune system. That helps it respond more effectively to the cutting-edge cancer drugs known as checkpoint inhibitors.

Checkpoint inhibitors work by removing the protein shield that tumors use to hide from a healthy immune system. While powerful medicines, they don't work for everyone, as some immune cells still fail to recognize the tumor as abnormal.

The new research suggests the COVID vaccine could act as a catalyst for patients' immune cells. 

"The vaccine acts like a siren to activate immune cells throughout the body," lead researcher Dr. Adam Grippin of MD Anderson in Houston told The Associated Press. 

"We’re sensitizing immune-resistant tumors to immune therapy,” he added.

More dedicated, patient-specific mRNA cancer vaccines to prime the immune system have been in development for years, but are not yet produced or used on a widespread basis. An “off-the-shelf” mRNA vaccine like the COVID-19 vaccine may be a readily available, low-cost alternative, researchers said.

For the study, they analyzed records of nearly 1,000 patients with advanced cancer who were receiving checkpoint inhibitors at MD Anderson, comparing those who had a COVID shot with those who didn’t.

They adjusted for 39 variables in order to tease out what effects the mRNA vaccine was having on patient outcomes, and rule out other things.

The data showed a dramatic benefit for those vaccinated within 100 days of starting immune checkpoint inhibitors:

• Overall Survival: Being vaccinated was tied to significantly improved overall survival (a median 37.3 months versus 20.6), as well as three-year overall survival (55.7% of patients versus 30.8%). 

• Lung Cancer: Vaccinated patients were nearly twice as likely to be alive three years after beginning cancer treatment compared to unvaccinated patients.

• Melanoma (Skin Cancer): Vaccinated patients showed a significantly longer median survival time, and many were still alive when the researchers looked at the data.

Importantly, the researchers found that non-mRNA vaccines, like the standard flu shot and pneumonia vaccines, didn’t make a difference.

Researchers now plan a larger, more rigorous study to confirm if mRNA coronavirus vaccines should be routinely paired with checkpoint inhibitors while they develop new, dedicated mRNA cancer vaccines.

Several study authors reported ties to the biopharmaceutical industry.

More information

The National Cancer Institute (NCI) provides resources on immunotherapy and cancer treatment research.

SOURCES: The Associated Press, Oct. 22, 2025; Nature, Oct. 22, 2025