mRNA vaccines - what is worth knowing about them? The outbreak of the COVID-19 pandemic meant that mRNA vaccines could be used on a large scale for the first time, while at the same time being an alternative to traditional vaccines. The advantage of mRNA vaccines is that they can be produced in a short time, which can be used in the fight against newly emerging epidemics. What exactly are mRNA vaccines and are they really safe for us?
What are mRNA vaccines?
mRNA vaccinesis a new type of drug thatis used to protect against infectious diseasessuch as COVID-19. The abbreviation mRNA stands formatrix or messenger ribonucleic acid (RNA)- a molecule that plays a very important role in each of our cells. Its task is to carry coded information about a specific protein in the cell. The task of the mRNA vaccine isto provide our cells with instructions on how to produce the protein of a specific pathogene.g. SARS-CoV-2 virus.
The very concept of using mRNA in the treatment of various diseasesappeared in 1989, when the biotechnological company Vical Incorporated from San Diegopublished studies showing that any mRNA produced in a laboratory can be successfully transferred to different cells.
It is worth noting that the advantage of mRNA vaccines over traditional vaccines is thatcan be developed and marketed much faster . This is because in the case of traditional vaccines, it is first necessary to thoroughly understand the entire genome of the pathogen and identify the proteins that are responsible for the immune response. Then you need to find a suitable method of propagating the pathogen under laboratory conditions. And only then the composition of the vaccine is developed, which will be widely distributed. This usually takes many years of research.
Types of mRNA vaccine
We candivide mRNA vaccines according to the way they are introduced into the body . The simplest method is to introduce the so-called naked mRNA, e.g. by subcutaneous injection. Then such mRNA is captured by cells, which can produce a protein based on it.
Another formintroducing an mRNA vaccine into the body isplacing the mRNA molecule in a lipid nanoparticle , which is a kind of protective layer. The use of such technology protects sensitive mRNAs from degradation. Moreover, the specific customization of the lipid nanoparticle enables mRNA to be taken up by specific cell types.These types of mRNA vaccines can be injected into the bodye.g. by intravenous or subcutaneous injection. Examples of this type of mRNA vaccine are those produced against COVID-19 by Moderna (mRNA-1273 vaccine), Pfizer-BioNTech (BNT162b2 vaccine) and CureVac (active ingredient zorecimeran).
Another form of introducing an mRNA vaccine into the body is placing it inthe so-calledHere,specially modified viruses, e.g. adenoviruses , constitute a protective layer for the mRNA molecule. Such a virus is completely harmless, because through genetic modifications it is deprived of infectivity and the ability to multiply in the cell. It can be said that it is merely aform of "means of transport" in which an mRNA molecule containing information about the pathogenfragment to which vaccine immunity is to be generated is inserted. In the case of the COVID-19 vaccine, it contains information about the SARS-CoV-2 virus spike protein (S for short). The viral vector, after entering the cell, stimulates the temporary production of the S protein in cells, and then it is broken down.
Examples of this type of mRNA vaccine are those produced against COVID-19 by AstraZeneca (AZD1222 vaccine) and Janssen Pharmaceutica (Ad26.COV2.S vaccine).
Read also:COVID-19 vaccines - a comparison. What's the difference between the Pfizer and Moderna vaccines?
How mRNA vaccines work?
In order to induce an immune response, many traditional vaccinesintroduce ready-made fragments (proteins) of the pathogen or whole pathogens subjected to the so-called attenuation(rendered harmless so that it does not cause disease). Instead,mRNA vaccines "train" ourcells to produce a protein, or a fragment of it, that triggers an immune response against the pathogen. The consequence of this is the production of specific antibodies against the virus that protect us against infection and the development of the disease. It thus mimics a natural virus infection. After making the protein and triggering an immune response, mRNA is removed from the cell.
Read also: Coronavirus vaccine. Types, availability and price
EffectivenessmRNA vaccines
The results of clinical trials indicate that mRNA vaccines areable to generate an immune response with a very high efficiency . For example, clinical trials evaluating the effectiveness of the Moderna vaccine against COVID-19 showed that the vaccine reduced the incidence of symptomatic COVID-19 disease by as much as 94%.
The disadvantage of some mRNA vaccines against COVID-19, e.g. from Pfizer / BioNTech, is that they require specific storage conditions during distribution. If these conditions are not met, the effectiveness of the vaccine may be affected.
Application of mRNA vaccines
Until December 2022, no mRNA vaccine was officially approved for human use. However, due to the unexpected COVID-19 pandemic, in December 2022 the British drug regulatory agency approvedthe first-ever mRNA vaccine from Pfizer / BioNTech .
Previously, research using mRNA vaccines was also done in the context of preventing diseases caused by viruses such as influenza, Ebola, Zika, HIV and rabies.mRNA vaccines can be produced in about a weekand against various pathogens, which is especially important in the context of the emergence of new epidemics.
In addition to infectious disease,mRNA vaccines have potential as new therapies for cancer patients . In this case, mRNA vaccines carry information not about pathogens, but about proteins of specific tumors. In this way, they stimulate the immune system to fight cancer cells such as leukemia, melanomas, gliomas and prostate cancer.
In addition, research is underway on the use of mRNA vaccines in the treatment of allergies.
Read also:Novavax vaccine - action, effectiveness. What do we know about this vaccine?
Safety of mRNA vaccines
The main advantage of mRNA vaccines is thatcan be produced in the laboratory in a very short timeand with little financial outlay compared to traditional vaccines. An additional advantage affecting the safety of mRNA vaccines is thatdo not contain particles of the entire pathogen or its inactivated form , which means that they are not potentially infectious.
In addition, mRNA vaccines have been shown to bewell tolerated in he althy people , with few side effects. Mild effects may occur after administration of both the lipid and vector nanoparticle mRNA vaccinesside effects in the form of: pain and swelling at the injection site, fatigue, headache, muscle pain and chills, joint pain, fever. Current clinical trials have not shown that mRNA vaccines are less safe than conventionally produced vaccines.
It is also false that the mRNA contained in a vaccine can integrate into our genome.Such integration is against the laws of molecular biology. The human genetic material is deoxyribonucleic acid, i.e. DNA, which is located in the cell nucleus separated by spaces from other cell structures, e.g. cytoplasm. In contrast, the mRNA from the vaccine remains only in the cytoplasm, where it is quickly degraded after being instructed about the protein.
Bibliography:
- Pardi N, Hogan MJ, Porter FW, et al. mRNA vaccines - a new era in vaccinology. Nat Rev Drug Discov. 2022; 17 (4): 261-279.
- Weiss R, Scheiblhofer S, Thalhamer, J. Generation and Evaluation of Prophylactic mRNA Vaccines Against Allergy. Methods Mol Biol. 2022; 1499: 123-139.
- Chahal JS, Kahn OF, Cooper CL, et al. Dendrimer-RNA nanoparticles generate protective immunity against lethal Ebola, H1N1 influenza, and Toxoplasma gondii challenges with a single dose. Proc Natl Acad Sci USA. 2016; 113 (29): E4133-42.
- Sahin U, Derhovanessian E, Miller M, et al. Personalized RNA mutanome vaccines mobilize poly-specific therapeutic immunity against cancer. Nature. 2022; 547 (7662): 222-226.
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