More than 100 cancer vaccines are now being tested in clinical trials, and many of them use the same mRNA technology that powered Covid shots. That puts a new class of treatment at the center of cancer research at a moment when immunotherapy is moving faster than it has in years.
The surge is easy to miss because it sits inside a broader boom. A global registry listed 1,257 immunotherapy trials from 2006 to 2016, and that number rose to 4,591 in the past decade. Cancer remains the biggest part of the field, with dozens of immunotherapies already approved for more than 30 types of cancer. For patients and trial participants, the question is no longer whether the immune system can be part of treatment. It is which version of that idea will work best, and for whom.
Cancer vaccines are designed to do one thing: stimulate the immune system so it recognizes tumours and attacks them. That approach now joins a wider set of treatments that use the body’s defenses rather than chemicals alone. Checkpoint inhibitors reactivate immune cells that tumours have switched off. Herceptin binds to breast and stomach tumours, flags them for destruction and blocks growth signals. Car-T-cell therapy engineers a patient’s immune cells to hunt down cancer cells, and last month Sam Neill said he was cancer free after receiving that treatment for stage 3 blood cancer as part of a trial.
Neill’s recovery shows why cancer immunotherapy has captured so much attention. But the field still has a stubborn gap in the middle of its success story. Some patients do extremely well, while others barely respond, and doctors still do not fully understand why. In 2018, doctors treated a woman with metastatic breast cancer by harvesting immune cells that had infiltrated her tumours, growing billions of the cells in the lab and putting the strongest ones back into her bloodstream. It was a striking result, but also a reminder that the same immune system can produce wildly different outcomes from one patient to the next.
That uncertainty is why the race to test cancer vaccines matters now. Researchers are not waiting for one perfect answer; they are running more than 100 shots at the problem, with mRNA-based designs among the most closely watched. Adrian Liston has said the excitement comes from a growing recognition of how important the immune system is, while Samra Turajlić has said cancer is increasingly being seen as something shaped by that system. The next proof point will not be a slogan or a breakthrough claim. It will be trial data showing which vaccines work, for which cancers, and whether this new wave can turn promise into treatment.
