The vaccine was developed by drug companies Merck & Co and Moderna. It was given to patients with high-risk melanoma, a type of skin cancer, after they had surgery.

Early results show this new jab extended the length of time these patients were cancer-free, but it's unclear for how long, according to an announcement by the two firms.

According to BBC, cancer experts say this is a breakthrough, but emphasise caution as the full results have not been released or peer-reviewed whereby independent experts examine and check the trial findings.

The vaccine works by alerting the immune system to mutated proteins, or neoantigens, found in tumours. Once flagged as foreign, the immune system hunts down and eliminates the cells carrying them.

The vaccine, called Intismeran, was given in combination with Merck's Keytruda, an immunotherapy drug already used in cancer treatment.

The companies reportedly said taking the drug (Keytruda) and vaccine together significantly increased the time patients remained cancer-free and reduced the risk of the disease spreading to other organs.

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The vaccine has boosted hopes that mRNA technology could open up a new avenue of cancer treatment, but the available evidence is still limited, Reuters reported on Wednesday.

Interim data from a large trial showed the experimental ​vaccine helped reduce the risk of melanoma recurrence and spread in ‌patients whose tumors had been surgically removed.

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How Does The Vaccine Work?

The vaccine is tailored to each patient's cancer rather than being a one-size-fits-all shot.

Doctors first remove the tumour and analyse its genetic makeup to identify mutations that are unique to that patient's cancer. The information is then used to make an mRNA vaccine designed to target up to 34 of those mutations.

The personalised vaccine is given alongside Keytruda, an existing immunotherapy. Patients can receive up to nine doses of each treatment, with Keytruda administered every six weeks.

The aim is to teach the immune system to spot the cancer's specific mutations and destroy cells carrying them.