mRNA Vaccines – A New Approach to Immunisation

The United Kingdom (UK) became the world’s first country to approve the Pfizer/BioNTech mRNA coronavirus vaccine on December 2 2020. Margaret Keenan, a 90-year-old female, became the first patient to receive the vaccine , with thousands of more such doses expected to be given to the people in the coming weeks. The Moderna vaccine is also an mRNA vaccine. A vaccine being developed by Pune-based Gennova became the first homemade mRNA candidate in India to get permission for human clinical trial.

The promise of mRNA or messenger RNA has fascinated researchers for decades . These tiny snippets of genetic code are essential in ordering  cells to build proteins, and this is key to unleashing the  human immune system. But they’ve been hard to tame, at least until the Covid -19 pandemic spurred the need to find an effective and safe vaccine .

What are mRNA vaccines, and how are they different ?

mRNA vaccines are a new type of vaccine in the armament of vaccines that we have,  to protect populations from communicable diseases. To date, most vaccines contain weakened or inactivated versions of the microbe, which ,when placed in the body, triggers an immune response.

mRNA vaccines  work in a completely different way.  They teach our cells how to produce, or make a protein, or even just a piece of a protein that triggers immune response inside our bodies. That immune response leads to antibodies’ production and protects us from getting infected if we are ever exposed to that microbe .

How do COVID-19 mRNA Vaccines Work?

COVID-19 mRNA vaccines teach our cells to make a harmless piece of the spike protein. This spike protein is the found on the surface of the virus that causes COVID-19. As soon as the COVID-19 mRNA vaccine is injected into the upper arm muscle,  the instructions (mRNA) are inside the muscle cells, and the cells use the instructions to make the protein piece. After the protein piece is created, the cell breaks down the instructions and disposes them of. After this, the cell shows the protein piece on its surface. The immune systems identify that this protein does not belong there and start building an immune response and produces antibodies, like what happens in natural infection against COVID-19. Towards the end of this process, our bodies have learnt how to protect against future COVID -19 infection.  The huge advantage that the person vaccinated gains is this protection without ever getting infected with COVID-19.

Pros and cons of mRNA vaccines

MRNA vaccines remove much of the manufacturing process since rather than having viral proteins injected, our body uses the instructions to produce viral proteins  by itself.  mRNA molecules are also far simpler compared to proteins. For vaccines, mRNA is produced by chemical rather than biological synthesis, thus it is much quicker compared to the conventional vaccines to be redesigned, scaled up and mass-produced.

The most significant challenge for developing a mRNA vaccine remains its inherent instability, as it is more prone to break apart above freezing temperatures. The Pfizer-BioNTech mRNA COVID-19 vaccine by will have to be optimally stored at minus 94 degrees Fahrenheit and may degrade in about five days at normal refrigeration temperatures of somewhat above freezing. On the contrary, Moderna claims that their vaccine can be maintained at most medical and home freezer temperatures for up to six months for shipping as well as longer-term storage.

Myths and Facts about COVID-19 mRNA Vaccines

• Myth : The vaccine can  cause COVID-19.

Fact  : mRNA vaccines do not use the actual  live virus that causes COVID-19.

• Myth: They affect our genes and DNA

Fact  : mRNA never enters the nucleus of the cell, which is where our DNA (genetic material) is kept. After an mRNA injection, this molecule guides the protein production inside the muscle cells, which reaches peak levels for 24 to 48 hours and can last for a few more days. After that , the cell gets rid of the mRNA.

mRNA Vaccines Are New, But Not Unknown

One may wonder how these mRNA vaccines have been created so quickly.  The fact is that researchers have been studying and working with them for decades. Interest has grown in these vaccines because they can be developed in a laboratory using readily available materials. This means the process can be standardized and scaled up, making vaccine development faster than traditional methods of making vaccines.

mRNA vaccines have been studied before for flu, Zika, rabies, and cytomegalovirus (CMV). Future mRNA vaccine technology may even allow for one vaccine to provide protection for multiple diseases, thus decreasing the number of shots needed for protection against common vaccine-preventable diseases. Beyond vaccines, cancer research has also used mRNA to trigger the immune system to target specific cancer cells.

mRNA vaccines are subjected to very stringent trials and safety standards  as all other types of vaccines . Therefore there is every reason to welcome this new technology in manufacturing vaccines and utilise its potential to help us conquer  COVID -19  at the earliest .