mRNA vaccines (named for the molecules used to carry their genetic information) consist of a strand of genetically engineered RNA that can be injected into muscle cells. mRNA vaccines use messenger RNA (mRNA), which delivers genetic messages from DNA to build proteins and instructions to cells to induce immunity against specific diseases.
mRNA vaccines are investigated for their use in cancer immunotherapy, infectious disease treatment and prevention, allergies, Alzheimer’s disease, and amyotrophic lateral sclerosis (ALS). mRNA vaccines may be used to deliver certain types of substances such as cytokines or antigens.
The history of mRNA vaccines
The history of mRNA vaccines could be described as an unfulfilled promise. Until recently, this was an umbrella term for several drug-development strategies in treating and preventing diseases.
Many academic institutions involved in researching RNA therapeutics do not use the term “mRNA vaccine.” Those who use it generally do not define what they mean by it. Some companies have developed their definition of what makes a vaccine an mRNA vaccine.
What is an mRNA Vaccine?
There is no consensus within the industry on a definition of mRNA vaccines. For example, AVI BioPharma defines an mRNA vaccine as “a unique type of pharmaceutical therapy that is designed to administer specific disease-fighting instructions through the body’s cells.”
In this case, the vaccine comprises RNA that causes cells to produce proteins that will fight viruses or cancer cells.
Pharmaceutical companies are investigating mRNA vaccines in clinical trials to treat conditions, including macular degeneration, amyotrophic lateral sclerosis (ALS), and prostate cancer.
Some academics define RNA vaccine platforms in terms of their therapeutic mechanism rather than what they deliver to patients.
For example, researchers at the University of Pennsylvania define RNA vaccines as “a novel class of therapeutics that harnesses the machinery used by all cells to translate mRNA molecules into protein and uses it instead to deliver potentially therapeutic RNAs.”
Advantages of mRNA Vaccines
- High levels of expression of vaccine proteins
- Rapid response to vaccination
- Avoidance of the production of pathogenic protein variants (such as avian influenza)
- Uncertain future and history
The term mRNA vaccine has been used for dozens of strategies that target gene therapy, cell therapy, and immunotherapy. It is partly why academic and commercial groups do not use the term.
- They may require more than one injection if they don’t work as intended or expected.
- May cause an immune response to healthy tissues, where the RNA sequences are similar to a disease-causing agent (such as tumor cells).
- Avoidance of some diseases may require multiple injections.
- Immune responses vary by individual, which could be problematic if the vaccine is not specific to a particular type or subtype of the disease.
- May cause side effects due to changes in protein expression that are intended for one purpose but result in another effect.
Although the history of mRNA vaccines is unfulfilled, researchers are still optimistic about its future. The technology can treat diseases that traditional methods cannot treat. However, many variables must be considered before becoming an alternative strategy for treating disease.