Introduction
Vaccines are considered one of the primary measures to prevent diseases and infections in humans. Nowadays, we hear a lot about the recently developed mRNA vaccines, such as Pfizer-BioNTech, Moderna, and others, which have been widely used for COVID-19 vaccination. However, traditional vaccines, such as those against measles, mumps, rubella, and many other diseases, have been around for decades. This blog post aims to provide a comparative study between mRNA vaccines and traditional vaccines, highlighting the key differences and similarities, to help readers make informed decisions.
Traditional vaccines
In general, traditional vaccines work by using weakened or inactivated viruses or certain proteins from the pathogen to stimulate the immune system to produce an immune response. The immune response then prepares the body to fight against the pathogen in case of future exposure.
Traditional vaccines are commonly divided into three types: live attenuated vaccines, inactivated vaccines, and subunit, recombinant, or conjugate vaccines.
Live attenuated vaccines contain the weakened form of the virus (or bacteria), which is still capable of replicating within the vaccinated individual but with low virulence. Examples of live attenuated vaccines include the vaccines against measles, mumps, and rubella (MMR).
Inactivated vaccines are made from killed viruses (or bacteria) or certain proteins from the pathogen. They cannot replicate within the vaccinated individual, but they still stimulate an immune response. Examples of inactivated vaccines include the vaccines against polio and hepatitis A.
Subunit, recombinant, or conjugate vaccines contain only specific pieces of the pathogen, such as proteins or sugars, that the immune system recognizes as foreign and develops an immune response against. Examples of subunit vaccines include the Hepatitis B vaccine and the human papillomavirus (HPV) vaccine.
mRNA vaccines
mRNA vaccines, on the other hand, use a different mechanism to stimulate an immune response. They work by introducing a small piece of the virus's genetic material, called mRNA, into the body. The mRNA instructs the cells to make the spike protein that is found on the surface of the virus.
Once the protein is produced, the immune system recognizes it as foreign and produces an immune response. This response prepares the body to recognize and combat the novel coronavirus, for instance, in case of future exposure.
mRNA vaccines have been shown to be highly effective in preventing COVID-19 and have several advantages over traditional vaccines, such as faster production time and a stronger immune response. However, they also have some limitations, such as the requirement for ultra-cold storage, which can be challenging in resource-poor countries.
Comparison
Here is a table comparing some key differences and similarities between mRNA vaccines and traditional vaccines:
| Parameters | mRNA vaccines | Traditional vaccines |
|---|---|---|
| Mechanism | Uses mRNA to produce a protein that triggers an immune response | Uses weak, killed, or pieces of virus/bacteria to activate immune response |
| Production time | Shorter production time | Longer production time |
| Immune response | Stronger and longer-lasting | Weaker and shorter-lasting |
| Efficacy | Highly effective | Effective (varies by vaccine type) |
| Cold storage requirement | Requires ultra-cold storage | Simple refrigeration or room temperature storage |
| Examples | Pfizer-BioNTech, Moderna | MMR, Polio, Hepatitis A, Hepatitis B, HPV |
Conclusion
In summary, mRNA vaccines use a different mechanism to activate the immune response compared to traditional vaccines. They have some advantages, such as faster production time and a stronger immune response, but they also have some limitations, such as the requirement for ultra-cold storage. Traditional vaccines have been around for decades and have a proven track record of success in preventing diseases and infections.
It is essential to note that both types of vaccines have undergone rigorous testing and have been shown to be safe and effective. Ultimately, the choice of which vaccine to receive depends on individual and geographical factors.
References
- CDC. Types of Vaccines. https://www.cdc.gov/vaccines/vac-gen/types.htm.
- Harvard Health Publishing. How do the COVID-19 vaccines differ? https://www.health.harvard.edu/blog/how-do-the-covid-19-vaccines-differ-2021052521705.
- Polack, F. P., et al. (2020). Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine. New England Journal of Medicine. https://www.nejm.org/doi/full/10.1056/NEJMoa2034577.
- Baden, L. R., et al. (2020). Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine. New England Journal of Medicine. https://www.nejm.org/doi/full/10.1056/NEJMoa2035389.