I think the medical definition of a vaccine is that it is a deactivated/dead suspension of the organism it’s designed to protect against.
Although mRNA vaccines don’t work like that. Instead they tell the body how to make harmless pieces of the cells we want to vaccinate against. But are still considered vaccines.

This cancer vaccine protects t-cells from being deactivated by these types of cancer, allowing the body to identify and deal with the cancer.
So not a vaccine in the “medical definition” sense, but it would still protect you from these cancers if you didn’t already have these cancers.
Although, I don’t know if it’s a “lesser of 2 evils” kind of treatment/vaccine where healthy people shouldn’t take it

I’m not sure exactly how this should be classed. According to the article it deactivates part of the cancer cells which then allows the patients own immune system to attack and destroy them.

So it isn’t really a treatment as it doesn’t destroy the cancer itself. The patient’s own immune system does that.

However a vaccine technically works by providing the immune system with the “blueprint” of the disease so the immune system knows how to destroy it if infected. Which isn’t what this is doing.

I suspect it probably has a long scientific name that average people won’t understand and makes for a crap headline.

My understanding is that a vaccine allows your immune system to create antibodies that fight off disease or infection. Some types of vaccines cannot be given while you have symptoms, but some can. It’s possible that whatever benefits the vaccine offers are part of a treatment that aims to eradicate the cancer over time (similar to chemotherapy or possibly in tandem).

Let it be known that I am not a medical professional and this is just what I’ve picked up as a random guy.

I didn’t read that article either, fuck their cookies… This press release from the NHS says treatment and doesn’t mention vaccine. I guess it’s a bad headline.