What Is an mRNA Vaccine?

A messenger RNA (mRNA) vaccine is a type of vaccine that is made without using an actual pathogen. Human cells contain millions of molecules called messenger RNA. mRNA provides instructions to the body to make proteins, such as the proteins in hair and nails.

Traditional vaccines typically use pathogens that are weakened or inactivated to mimic a real infection and trigger an immune response in the body. mRNA vaccines, however, do not use actual pathogens. Instead, they instruct the body to make a viral protein. The body creates antibodies to this protein to induce immunity.

The first COVID-19 vaccine authorized for use in the United States uses this newer type of vaccine known as mRNA; however, mRNA vaccine research has been around for years. Early-stage clinical trials have been carried out using mRNA vaccines for influenza, Zika, rabies, and cytomegalovirus (CMV).

Benefits

Compared to vaccines that use weakened or inactivated pathogens, the benefits of mRNA vaccines include the following:

• mRNA vaccines are safe and do not cause infections. They are non-infectious because they do not contain actual pathogens.
• mRNA vaccines have shorter manufacturing times, lowering the cost of production compared to traditional vaccines. Because mRNA vaccines are produced in a laboratory, the production process can be standardized and scaled up to allow for quick deployment.
• mRNA vaccines can be used to target multiple diseases.

Risks

Many of the risks from mRNA vaccines are similar to traditional vaccines:

• mRNA vaccines can trigger strong inflammatory responses.
• mRNA vaccines can trigger allergic reactions.
• mRNA vaccines may degrade quickly and may be sensitive to temperature changes.

A common misconception is that mRNA vaccines can potentially affect DNA. However, DNA is stored in the nucleus of individual cells; an mRNA vaccine does not enter the nucleus. Therefore, mRNA vaccines do not alter or interact with DNA.