What are the two main types of COVID-19 vaccines?

The two main types of COVID-19 vaccines are mRNA vaccines and viral vector vaccines.

mRNA vaccines, such as the Pfizer-BioNTech and Moderna vaccines, utilize messenger RNA to instruct cells to produce a protein similar to the spike protein found on the surface of the coronavirus. This process triggers an immune response, preparing the body to fight off the virus if exposed in the future.

Viral vector vaccines, like the Johnson & Johnson vaccine and the AstraZeneca vaccine, use a harmless virus (not the coronavirus itself) as a delivery system to introduce genetic material from the coronavirus into the body. This stimulates an immune response similar to that generated by mRNA vaccines but through a different mechanism.

These two types represent the cutting-edge approaches in vaccine technology for COVID-19, effectively training the immune system to recognize and combat the virus. Other types of vaccines, such as inactivated or protein-based, are more traditional and were not the focus of the initial COVID-19 vaccine rollout.