What is mRNA and how do mRNA vaccines work?

An mRNA vaccine is a type of immunisation that uses a copy of messenger RNA to produce an immune response. The vaccine transfects molecules of synthetic RNA into immunity cells.  

Put simply, mRNA vaccines work by providing a genetic code to cells that allow them to produce viral proteins. Once the proteins have been created, the body is then able to form an immune response to protect against the virus, enabling the body to develop immunity.   

One of the main advantages of mRNA vaccines is that they can be a lot quicker to produce than traditional vaccines. Getting the body to produce the protein, rather than creating the protein in a lab, cuts out some of the manufacturing process, making upscaling of production more straight-forward and making it possible to vaccinate on a large scale within a short period of time. This shortened manufacturing process also makes mRNA vaccines cheaper to produce than traditional methods and less vulnerable to unnecessary batch losses due to batch-to-batch variability. As this manufacturing process is sequence dependent, it highly adaptable to different viruses. As use of the technology becomes more widespread, the cost of producing a vaccine through mRNA is expected to decrease.  

Unlike viral-vectored vaccines, mRNA vaccines are considered safer because they are not infecting the person receiving the immunisation with the virus. Other methods also require chemicals and cell cultures to produce an immunity response; whereas mRNA is created through a cell-dependent process, which does not require inactivation, so there is no risk of contamination with potentially toxic agents.  

While it is still early days with mRNA vaccines, they have been proven to be highly effective in preventing disease. Research has shown that compared to traditional vaccines, mRNA vaccines can generate a strong form of immunity as they stimulate the immune system to produce not just antibodies, but also killer cells, generating a more effective response.  

The success of the Covid-19 vaccines, that were first approved in 2020, has made scientists extremely optimistic for this new era in vaccination technology. Research has demonstrated mRNA vaccines potency and versatility to protect against a wide variety of infectious viruses, including viruses such as influenza, Ebola and Zika.   

In addition to its application in infectious diseases, scientific researchers have been pursuing the potential for mRNA vaccines to treat conditions such as cancer. In the same way that we can train our immune systems to recognise viral proteins, we could also use the technology to train them to recognise proteins on cancer cells. This approach would allow treatments to be personalised as scientists could study the cells of a specific person’s tumor and create a custom-made treatment that would help that individual’s own immune system defeat the cancer. However, this is no simple solution because there is often no clear protein target in cancer, yet ongoing clinical trials are showing mRNA to be effective for some cancer treatments such as melanoma. 

In the future, mRNA therapies could also be available for rare diseases that are currently untreatable. If scientists can identify the genetic cause of a disease, in theory they should be able to go and edit that out and repair it using mRNA-based technology, but research into this area is still ongoing.