The COVID-19 vaccine may offer brain cancer patients a surprise benefit

The COVID-19 vaccine may give brain cancer patients a bonus shot at survival.

Patients who received the vaccine within 100 days before biopsy or tumor surgery lived twice as long as those who didn’t get the shot, scientists report July 31 at medRxiv.org. This link existed only for COVID-19 vaccines, not other vaccines that the team investigated.

The discovery suggests that the COVID-19 vaccine might be somehow firing up the immune system’s cancer-fighting powers, says James Markert, a neurosurgeon at the University of Alabama at Birmingham. But he’s quick to point out that his team’s paper, a preliminary study that has not yet been peer-reviewed, found an association between vaccination and survival — it did not show cause and effect.

Still, evidence is mounting that mRNA COVID-19 vaccines may spur anti-cancer action, says Elias Sayour, a pediatric oncologist at the University of Florida College of Medicine in Gainesville, who was not involved with the new study.

Last year, Sayour’s team linked mRNA COVID-19 vaccination with extended survival in patients with other types of cancer. People with lung cancer or melanoma who were vaccinated within a few months of immunotherapy lived nearly twice as long as their unvaccinated counterparts. The latest study adds more evidence to the pile. “I think it’s very interesting and I think it’s very important,” Sayour says.

Markert’s team examined data from 187 people with glioblastoma, an aggressive brain cancer with no cure. All patients had their brain tumors biopsied or surgically removed from 2022 to 2025. While half of those vaccinated before surgery lived 743 days or longer, for unvaccinated patients, the median survival was just 349 days. For glioblastoma patients, who have few treatment options, that amounts to an extra year of life.

The researchers tried to control for factors such as the severity of any COVID infections and whether COVID-vaccinated people had better health care than their unvaccinated peers. But it’s impossible to account for everything, Markert says, leaving it unclear exactly what is going on.

COVID vaccines may be rousing the immune system to come after cancer. Previous studies have hinted that mRNA-based vaccines in particular could be prompting this immune action. And in both Markert’s and Sayour’s studies, non-mRNA vaccines, like those for flu and pneumonia, did not give cancer patients the same survival boost. 

In the case of the glioblastoma study, perhaps surgery itself is helping spark an immune effect, the researchers say. Before surgery, the cancer is hidden away in the brain. But it’s possible that cutting into the tumor releases bits of cancer proteins into the bloodstream, exposing it to the newly revved-up immune system.

The team wants to figure out if the vaccine acts like an alarm bell that wakes our immune defenders generally or a teacher instructing immune cells to specifically target glioblastoma. Preliminary data point to a possible role for teaching. mRNA COVID vaccines teach the immune system to recognize a snippet of coronavirus protein, and Markert’s team discovered a molecule on glioblastoma cells with a similar shape. So an immune lesson in spotting coronavirus might double as a lesson in spotting brain cancer.

Markert and his colleagues are now attempting to validate their findings in a different group of patients. If that pans out, he is interested in a clinical trial that directly tests how the COVID-19 vaccine affects brain cancer patients.

Sayour and his colleagues are already moving forward with a trial that looks at whether an mRNA COVID vaccine boosts the benefits of immunotherapy in patients with advanced non-small cell lung cancer. If a large, randomized clinical trial were to one day show that a widely available and affordable vaccine like the COVID one extends cancer patients’ survival, that would be “earth shattering,” he says.

At this point, scientists cannot say whether that’s true or not. And no one is suggesting that cancer patients should delay surgery or other treatment until they get vaccinated, says Sivakrishna Uppalapati, a cancer researcher who works with Markert.

But when it comes to glioblastoma, Markert says he’s grateful for any new lead: “We think this provides hope.”