At the time of this writing, the worldwide death toll from COVID-19 has exceeded 10,000 people. As spread of the disease escalates, a phase 1 clinical trial of an investigational vaccine using an RNA vaccine has begun in Seattle, Washington.

Conventional vaccines typically employ antigens – inactivated disease-promoting organisms or proteins produced by a virus or bacterium. Antigens mimic the infectious agent to provoke an immune response and provide immunity from future exposures.

RNA vaccines, on the other hand, utilize a messenger RNA (mRNA) strand that codes for a disease-specific antigen. The vaccine delivers the mRNA strand to the body’s cells, where the genetic information is used to produce the antigen. Similar to the conventional vaccine-derived antigen, these cell-derived antigens drive an immune response.

The phase 1 clinical trial involves approximately 45 healthy men and women between the ages of 18 and 55 years. The study participants will be enrolled into one of three cohorts to receive either a 25 microgram (mcg), 100 mcg, or 250 mcg dose, via intramuscular injection in their upper arm. A repeat dose will be given four weeks later. The patients will be monitored via follow-up visits after the vaccinations to gauge the vaccine’s safety and effectiveness.

The mRNA vaccine used in this trial, known as mRNA-1273, has shown promise in animal studies, but this is the first trial to test it in humans. Enrollment has already begun for the trial. If you live in the Seattle area and would like to participate, read this information.

• Full description of the clinical trial.

• More information about mRNA vaccines.