If you had to pinpoint the most transformative medical innovation of the past few centuries, the invention of the vaccine would be a strong contender. Deployed against polio, measles and influenza, vaccines are thought to have saved hundreds of millions of lives since the 1790s, when Dr Edward Jenner first noticed that milkmaids who contracted cowpox tended not to develop the more serious smallpox. But there’s one disease that vaccine scientists have never, yet, worked out how to conquer: cancer.

Governments in the 2000s poured large sums into the hunt for ‘cancer jabs’, described by some as the holy grail of cancer research. But they made little demonstrable progress.

Now, that might be changing. Recently, charities praised ‘historic’ results from the first major study into the effects of the vaccine used to prevent human papillomavirus (HPV), which is cutting rates of cervical cancer by nearly 90 per cent, according to data published in the Lancet. Scientists say there’s more momentum towards cancer vaccines now than ever before, thanks partly to Covid-19 lighting a rocket beneath the industry. "The technology has leapt on," says Dr Sam Godfrey, senior research manager at Cancer Research UK. "The past year and a half has given us insight into things we didn’t know before. We’ve tested things faster, developed technologies quicker; pushed things in ways we haven’t before."

So which cancers might we one day be able to beat with vaccines?

Cervical, head and neck, anal and genital cancers

There was scepticism in the medical community in the early 1990s, when the first scientists suggested that cervical cancer might be linked to HPV, a common group of viruses spread through skin-to-skin contact or sex. HPV sometimes causes warts on the skin, but other than that was thought to be broadly harmless. But then, in 1999, UK epidemiologist Prof Julian Peto proved that almost all cases of cervical cancer are linked to HPV.

In some cases, HPV can lie dormant for decades, hiding from the immune system, gradually inflicting damage on this defence system. Eventually, if you’re unlucky, cancer develops.

The logic behind the HPV vaccine was simple: eliminate the virus, and we might just be able to eliminate cervical cancer, too. And it seems to have worked. "It’s a big deal," says Godfrey.

Breast cancer

It’s among the most commonly diagnosed cancers in the UK; now scientists think breast cancer might be tackleable with vaccines.

Researchers in the US launched a well-publicised trial, testing a new vaccine against the most aggressive form of breast cancer, triple-negative. The vaccine will target a protein called a-lactalbumin, which plays a key role in the production of breast milk, and is usually only produced by the body during pregnancy and lactation.

But a-lactalbumin is also commonly found in breast tumours, meaning it could function as an early alarm. The technology has already proved successful in mice.

Melanoma

Some of the most exciting research is now looking at how cancer vaccines can be ‘personalised’ to fight the specific antigens that live on each patient’s tumours.

Scientists at Harvard University are currently working on personalised vaccines designed to fight melanoma, the deadliest form of skin cancer.

They have already developed specially tailored vaccines for eight patients, all of whom had had their melanoma surgically removed (and thus remained in the ‘high-risk’ group).

The research team then followed the patients and saw the vaccines maintained their immune effect for years after the initial injection.

The Daily Telegraph

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