The company said its new candidate, mRNA-1283, could potentially be stored in refrigerators instead of freezers, making it easier to distribute, especially in developing countries.
The early-stage study will assess the safety and immunogenicity of mRNA-1283 at three dose levels, and will be given to healthy adults either as a single dose or in two doses 28 days apart, the company said.
Last week, Moderna began dosing the first participants in a study testing its COVID-19 booster vaccine candidates.