mRNA, INACTIVATED, and VIRAL VECTOR VACCINES?

by Kausalyaa Kaliapan

Numerous research efforts by the scientific community, private companies, and international governments led to the development of various COVID-19 vaccines at record speed.

The three most well-known vaccines are mRNA vaccines, viral vector vaccines, and inactivated vaccines. But, how do they differ from each other? What are the differences in their mechanisms and functions? These questions have been a source of confusion for the public when asked to get vaccinated. All these vaccines differ in their composition and production methods.

The Pfizer/BioNTech and Moderna vaccines are mRNA vaccines approved for human use. These mRNA vaccines offer targeted immunity. They contain strands of genetic material called messenger RNA (mRNA). This mRNA instructs our body to produce a harmless version of the spike protein found in the Covid-19 virus.

So, when our body detects the spike protein, it will start creating antibodies to defend against it. The mRNA is naturally broken down and eliminated by the body.

In contrast, viral vector vaccines use a safe virus to deliver specific proteins of the COVID-19 virus to trigger an immune response without causing disease. For instance, the AstraZeneca and Johnson & Johnson vaccines are viral vector-based. In these vaccines, target material from the COVID-19 virus is placed in a modified version of another virus, the viral vector.

The viral vector instructs cells to produce copies of the Covid-19 specific protein, the S protein. Our immune system will then create antibodies in response to the S protein displayed on the surfaces of our cells.

On the other hand, inactivated vaccines, such as those produced by Sinovac, are created using proteins or other small components derived from the virus. This is a common vaccine production method that involves inactivated vaccine technology, where the coronavirus particles are killed and rendered inactive.

These inactive particles cannot cause disease but still stimulate our bodies to produce antibodies as an immune response. This method is similar to
those used to produce other vaccines, such as the polio vaccine and the hepatitis A vaccine. The inactivated virus acts as a harmless trigger, prompting the immune system to recognize and fight the actual virus if encountered in the future.

In conclusion, it is important to note that none of these vaccines can cause a Covid-19 infection. They are designed using different scientific approaches to either prevent infection or to significantly reduce the severity of symptoms if an infection does occur. Each method has been rigorously tested to ensure safety and efficacy, offering a multifaceted defence against Covid-19.