To mark World Immunisation Week, we’re sharing this latest blog as part of our ongoing #CelebrateVaccines campaign, which explores vaccines from major public health successes to future innovations. This post focuses on mRNA vaccines and the exciting possibilities they offer.
The principle of vaccination – using harmless pieces of harmful things to train the immune system to better fight threats – is no longer limited to just combatting infections. Scientists are now looking to the future of vaccines, and how they could treat or prevent other, non-infectious, diseases.
The key to this vaccine revolution is a technology that skyrocketed into the limelight during the COVID-19 pandemic, but had been in development for decades – mRNA vaccines.
The future of vaccines – mRNA
mRNA (messenger ribonucleic acid) has been a key component of all life on earth for billions of years. In our bodies, it carries instructions that tell our cells how to make proteins. mRNA vaccines use this natural process to train the immune system.
Instead of introducing a weakened or inactive form of a virus (like with traditional vaccines), mRNA vaccines deliver instructions that tell cells to produce a harmless piece of it themselves. The immune system recognises this protein as foreign and learns how to respond, so it can act quickly if it encounters the real disease in the future (see image A).
mRNA vaccines gained notoriety during the COVID-19 pandemic; both the Pfizer/BioNTech and Moderna vaccines used the technology. However, the first mRNA vaccine tests in humans happened in 2013, and animal tests were happening as far back as the 1990s (see image B).
One of the key advantages of mRNA vaccines is how quickly they can be designed and produced. This makes them particularly useful in responding to emerging diseases or outbreaks, such as the COVID-19 pandemic. They can also generate strong immune responses, making them a promising platform for tackling diseases that have been difficult to target with traditional vaccines, like HIV and malaria.
Because of this flexibility, researchers are now exploring how mRNA technology could be used beyond infectious diseases, including personalised medicine for conditions like cancer or autoimmunity.
Cancer vaccines
Cancer remains one of the leading causes of death worldwide, with nearly 10 million deaths each year, with cases expected to rise.
For many patients, treatment is not just physically demanding but emotionally exhausting. Chemotherapy and radiotherapy can be effective, but they often come with severe side effects, placing additional strain on patients and the people around them.
A more targeted approach
Cancer vaccines are now being explored as a more targeted alternative. Unlike vaccines that prevent infectious diseases, they are designed to help the immune system recognise and attack existing cancer cells. In some cases, they may also help prevent cancer from returning after treatment.
One of the challenges in treating cancer is down to the mutations that occur in cancer cells. These mutations are unique to individuals, meaning people need to try different treatments before finding one that’s effective. Traditional treatments that target one mutation might also stop working as more mutations occur over time. However, personalised mRNA cancer vaccines aim to address these problems.
Additionally, the rapid production process for mRNA vaccines makes them highly effective against fast-mutating tumours, while still maintaining strong safety profiles. Some mRNA cancer vaccines can be made in as little as two months, with one clinical trial producing them in just 28 days!
This precision also has important implications for quality of life. Because mRNA vaccines are designed to target cancer cells specifically, they may reduce the risk of unpleasant side effects, easing the burden on patients and their families.
How cancer vaccines work
The process is highly personalised. After a biopsy, the tumour’s genetic code is analysed and used to create a personalised mRNA sequence. Once delivered into specialised immune cells, this mRNA instructs the body to produce markers that train the immune system to recognise and attack the cancer with accuracy (see image C).
Progress and future outlook
By 2025, over 60 RNA-based cancer vaccines were in development and more than 120 clinical trials were underway (including some in the UK!), with promising early results.
For example, patients with advanced kidney cancer receiving mRNA cancer vaccines remained cancer-free for over 34.7 months, and 10 of 14 breast cancer patients receiving mRNA cancer vaccines remained cancer-free for up to 3.5 years. When combined with other treatments, mRNA cancer vaccines were shown to reduce the risk of skin cancer recurrence or death by up to 44%.
With the first approvals expected by 2029, this could offer a new option for those not helped by conventional treatments.
mRNA cancer vaccines enhance the body’s capability to fight cancer. But what if you needed to suppress the immune system? mRNA vaccines, once again, might hold the key.
Autoimmunity ‘reverse’ vaccines
In autoimmune conditions, the immune system mistakenly attacks the body's own healthy cells. Around 1 in 10 people worldwide are affected by at least one autoimmune condition, and cases are rising.
Current treatments work by suppressing the entire immune system, but this leaves patients vulnerable to infections or cancer. Researchers are now developing more precise approaches; vaccines that, rather than training the immune system to recognise a threat, teaches it to see something as safe without silencing the entire immune system – so-called ‘reverse vaccines’.
How reverse vaccines work
In reverse vaccines that use mRNA vaccine technology, scientists remove the ‘danger’ signals from the disease-linked mRNA that would normally trigger an immune response. When introduced into the body, this helps retrain the immune system to ignore those targets rather than attack them.
A different strategy involves targeting immune cells directly. One study used mRNA that makes a protein called FoxP3 - this protein is linked with a type of T cells that regulate the immune system. Increasing the number of cells making FoxP3 could boost the number of these special T cells, and might help control the self-destructive immune response.
See image D for a summary of how these two approaches work.
Potential and early results
Reverse vaccines generally have longer-lasting effects than more traditional immune suppression, which typically needs frequent doses (sometimes even daily), and can cause severe side-effects. Because of this, some are even seeing reverse vaccines as a potential cure for autoimmunity, rather than just a tool for symptom management.
The field of reverse vaccines is relatively new, but researchers are excited about its potential! In 2023, an mRNA reverse vaccine delayed type 1 diabetes-like symptoms in mice and in 2025, a reverse vaccine against multiple sclerosis showed beneficial effects in mice. Compared to the treatment options a decade ago, the future of autoimmune treatment is looking bright thanks to reverse vaccines.
From a technology fast-tracked due to the COVID-19 pandemic comes the potential for novel treatments for some of medicine’s trickiest challenges. As the field of mRNA vaccines continues to grow, we can’t wait to see what discoveries will give us even more reason to #CelebrateVaccines.
By Ellie Pearson, former Intern at the BSI