What is the Difference Between Viral Vector and mRNA Vaccines?

🆚 Go to Comparative Table 🆚

The main difference between viral vector and mRNA vaccines lies in the way they deliver genetic material to the cells. Here are the key differences between the two types of vaccines:

  1. Delivery Method: Viral vector vaccines use a harmless virus as a carrier to deliver genetic material into the host cells, while mRNA vaccines rely on non-viral vectors, such as lipid nanoparticles, for gene delivery.
  2. Genetic Material: In viral vector vaccines, the genetic material is DNA, which contains the code for making the viral spike protein. In mRNA vaccines, the genetic material is mRNA, which directly triggers the synthesis of the viral spike protein in the recipient.

Both types of vaccines work by providing the host cells with the necessary information to produce proteins (viral spike proteins) that stimulate an immune response in the body. Examples of viral vector COVID-19 vaccines include AstraZeneca, Johnson & Johnson, and Sputnik, while mRNA COVID-19 vaccines include BioNTech/Pfizer and Moderna.

Comparative Table: Viral Vector vs mRNA Vaccines

Here is a table comparing the differences between viral vector and mRNA vaccines:

Feature Viral Vector Vaccines mRNA Vaccines
Construction Based on viruses as natural vector systems, using harmless viruses to enter cells and hijack them, causing them to make proteins based on their genetic blueprint Based on non-viral vectors, such as lipid nanoparticles, which need another carrier for gene delivery
Mechanism Use replication-deficient viral vectors to deliver genetic material of a particular antigen to the host cell Directly trigger the synthesis of the viral spike protein in receivers
Immune Response Elicit potent antibody and cellular responses, crucial for the elimination of pathogen-infected cells Induce potent antibody responses
Delivery Method Viral vectors act as vaccine carriers, delivering the genetic material of a particular antigen to the host cell mRNA vaccines rely on non-viral vectors, such as lipid nanoparticles, for gene delivery
Vector Types Adenovirus, vesicular stomatitis virus, vaccinia virus, adenovirus associated virus, retrovirus, lentivirus, cytomegalovirus, and sendai virus have been used as vectors Not applicable

Both viral vector vaccines and mRNA vaccines rely on the delivery of genetic material to the host cells, but they differ in their construction and mechanism of action. Viral vector vaccines use viruses as natural vector systems, while mRNA vaccines use non-viral vectors for gene delivery.