What is mRNA Vaccine Technology?
In the recent covid19 pandemic, different vaccines came into the market to halt the spread of the infection. But two of them use a different approach than traditional vaccination methods. Pfizer-BioNTech and Moderna vaccines against covid19 used Novell messenger RNA (mRNA) technology.
Although They are the first vaccines based on mRNA technology to get approval by FDA, Work and study on mRNA technology-based vaccines have been going on for decades. Before we talk about mRNA vaccines, let’s look at what vaccines are and how they work?
Vaccines work by stimulating our immune system. When any harmful pathogen attacks our body (bacteria or viruses), Our immune system takes some time to fight back by making antibodies against the foreign invaders and storing them as immunological memory.
Hence, our immune system responds immediately on the second encounter with that particular infectious agent.
Vaccines trick our immune system into producing antibodies against a particular organism without getting us infected.
Conventional Vaccines work by introducing any part of the germ or the germ itself that is either weekend or dead into our body to train our immune system how to encounter the actual infection by producing antibodies against the particular antigen.
mRNA vaccine also does the same thing that instructs our immune systems to produce antibodies against a particular pathogen, but it takes a different approach than traditional vaccination methods.
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DNA is a molecule that contains all the genetic information necessary for the growth, function and reproduction of an organism. But it is secure in the nucleus of the cell.
To transfer its information from the nucleus to the cytoplasm where protein making machines ribosomes are present, we need another molecule called mRNA.
mRNA is synthesized in the nucleus using DNA as a template to transfer the genetic information to the cytoplasm for protein synthesis.
As soon as the mRNA message has been read and the protein building process begins, mRNA is destroyed by the body enzyme RNases, which ensures that cells don’t make too many copies of a single protein.
mRNA vaccine works by introducing a genetically engineered mRNA that corresponds to viral protein into our body and instructs our body to produce foreign(viral) proteins or just pieces of protein that trigger immune responses. As a result, antibodies are produced to protect us from future infections.
In the case of covid19, the mRNA vaccine tells the body to make SARS-CoV-2 spike protein present on the virus’s surface that causes covid19.
The spike protein then starts to display on the cell’s surface, and our body recognizes that it does not belong here and, as an immune response, starts to make antibodies against it.
After delivering its command to the body, the mRNA has been destroyed immediately by the body enzyme, and it will never enter the nucleus where our DNA is located.
Benefits of mRNA Vaccines
Unlike conventional vaccination methods, mRNA vaccines are faster and cheaper to produce.
Because they are made up of non-infectious material, there is no need for a culturing process to produce them.
They can quickly develop in a laboratory with readily available material in a shorter period.
These vaccines are beneficial in pandemic scenarios where we need a vaccine in a short period.
Theoretically, The basic technology behind mRNA vaccines is adjustable, so in case of new Mutation in existing viruses or the discovery of whole new viruses, it will be quick to update.
Since mRNA vaccines are based on sequences of viral proteins, making a new vaccine could require changing the mRNA sequence of the desired protein you want to make.
Unconventional vaccination methods require many viruses to grow in the laboratory, which can cause potential hazards. In contrast, only a few viruses are required in mRNA vaccine technology for gene sequencing and vaccine testing.
Challenges of mRNA Vaccines
The concept of the mRNA vaccine first emerged in the 1990s. However, because of the complexity of mRNA’s inherent instability and delivery difficulties and other factors, the field did not make noteworthy progress until the past decade, when advancements in technology and investment led to significant development.
The delivery of mRNA vaccine into the body is the biggest challenge; its large size and negative charge cause hindrance in its membrane permeability.
In addition to this, mRNA is easily degraded by extracellular ribonucleases.
To protect the molecule from digestion and increase its permeability, encapsulation in the carrier is very important.
Lipid-based vectors, such as liposomes and lipid nanoparticles (LNPs), are the most widely used mRNA delivery tools.
One of the mRNA vaccine undesired effects is that the foreign mRNA strands may elicit an involuntary immune reaction (interferon type I response), leading to fevers or chills. It could minimize these reactions by modifying and purifying the RNA molecules during manufacturing.
RNA vaccines need to be frozen or refrigerated at shallow temperatures.
The Moderna and BioNTech/Pfizer SARS-CoV-2 vaccines are kept at -20°C or -80°C throughout their lifecycle.
The thermal instability of mRNA vaccines is due to the inherent instability of mRNA molecules, which readily cleave at room temperature. When this occurs, the mRNA degrades, drastically reducing the vaccine’s efficacy.
This requirement for cold storage puts on challenges to the supply chain and administration of a global vaccine program. It increases the costs of vaccine transport and storage, but it also limits the reach and distribution of vaccines in areas that lack adequate transport and electrical infrastructure. The most crucial challenge to overcome with an mRNA-based vaccine is its thermal stability.
Work is in progress to produce reliable vaccines that can store outside the cold chain since these will be much more suitable for use in countries with limited or no refrigeration facilities.
Future of mRNA Vaccine
Before the pandemic, mRNA technology was considered a good concept, but there were always doubts that it would deliver the results.
Now all the doubts are clear, and there is growing confidence that mRNA vaccines could have profound applications in controlling diseases from flu to cancer.
This vaccination approach also shows promising results against old rivals such as HIV and infections that threaten babies and young children, such as a respiratory syncytial virus (RSV) and metapneumovirus.
It’s also being tested to treat cancers, including melanoma and brain tumors.
Perhaps it will show a new way for the treatment of autoimmune diseases.
Vaccines are being used for an extended period to prevent many infectious diseases. With the help of vaccination, we successfully eradicate smallpox and reduce polio cases by up to 99%from the world.
The conventional vaccine has always proved very useful in controlling different infections. However, this new technology of mRNA vaccines represents a promising alternative to conventional vaccine approaches because of their high potency, capacity for rapid development and potential for low-cost manufacture and safe administration.
 What is a vaccine? Types, stages for approval – Medical News Today
 The Long History of mRNA Vaccines – JHU
 What are mRNA vaccines and how do they work? – Medline Plus