A retrospective analysis published in Nature suggests that people treated for certain cancers, including melanoma and lung cancer, lived significantly longer if they had received an mRNA-based Covid-19 vaccine before or shortly after starting immunotherapy. The findings hint that mRNA vaccines - initially designed to prevent infection - might also amplify anti-cancer immune responses.
Researchers at the MD Anderson Cancer Center in Houston, Texas, US, found that patients who had been vaccinated with an mRNA Covid-19 vaccine within 100 days of beginning treatment with immune checkpoint inhibitors survived markedly longer than unvaccinated counterparts. The effect was especially pronounced among individuals with tumours thought to respond poorly to immunotherapy.
“The Covid-19 mRNA vaccine acts like a siren and activates the immune system throughout the entire body,” said Adam Grippin, a radiation oncologist at MD Anderson and co-author of the report. “We were amazed at the results in our patients.”
The study reviewed the medical records of more than 1,000 people with either metastatic melanoma or lung cancer. For patients with a specific type of lung cancer, vaccination was associated with an increase in median survival from 21 months to 37 months. Among those with metastatic melanoma, vaccinated patients lived so long that the researchers could not yet calculate an average survival time.
This correlation did not extend to individuals who received other types of vaccines, such as influenza or pneumococcal inoculations, nor to those treated with non-immunotherapy regimens.
Animal experiments provided a possible biological explanation. The team demonstrated in mice that the mRNA vaccine’s lipid nanoparticle formulation stimulated the immune system in a manner that enhanced the tumour-fighting effects of checkpoint inhibitors. These drugs release the brakes on the immune system, allowing killer T cells to attack cancer cells more effectively.
Independent experts described the data as striking. “I did not expect the effect to be that significant, and the data are very strong,” said Benoit Van den Eynde, a tumour immunologist at the University of Oxford.
Timing appeared to be a key factor. Patients vaccinated within 100 days of starting treatment gained the most benefit, and early unpublished data from Grippin’s group suggest that the optimal window may be as short as 30 days before or after therapy initiation.
The researchers emphasised that the observed benefit did not arise from protection against Covid-19 itself, but from the broader immune activation triggered by the vaccine’s mRNA and lipid nanoparticle components.
These findings come at a time when mRNA research funding has been sharply curtailed. According to the report, the US administration under President Donald Trump recently cut approximately $500 million in federal funding for mRNA-related studies. “The current climate impacts patients because even the word, ‘mRNA’, has stigma these days,” said Steven Lin, another oncologist and study co-author. “We’re walking on eggshells because there’s so much negative publicity about mRNA.”
If validated in clinical trials, this discovery could offer a widely available and cost-effective strategy to enhance cancer immunotherapy.
- By Rosie Bannister