What happened
Shares of Moderna (MRNA -0.22%) climbed on Tuesday after the biotechnology company announced the start of a clinical trial for its COVID-19 vaccine in children aged 6 months to 11 years. As of 12:45 p.m. EDT, Moderna's stock price was up more than 8%.
So what
Moderna's vaccine, mRNA-1273, is currently authorized for emergency use in adults aged 18 and older. The drugmaker began testing its safety and effectiveness in adolescents 12 to 17 in December. And on Tuesday, Moderna said it dosed the first participants in a phase 2/3 study of mRNA-1273 in younger children.
Moderna plans to enroll roughly 6,750 participants in the study. Each child will receive two doses of mRNA-1273 given 28 days apart, with the first at one of three dose levels: 25 micrograms, 50 micrograms, or 100 micrograms. The participants will be monitored for one year after their second dose.

Moderna's share price rose sharply on Tuesday. Image source: Getty Images.
The National Institute of Allergy and Infectious Diseases (NIAID) and the Biomedical Advanced Research and Development Authority (BARDA) will help to conduct the trial.
"We are encouraged by the primary analysis of the Phase 3 COVE study of mRNA-1273 in adults ages 18 and above and this pediatric study will help us assess the potential safety and immunogenicity of our COVID-19 vaccine candidate in this important younger age population," Moderna CEO Stephane Bancel said in a press release.
Now what
Safe and effective coronavirus vaccines such as mRNA-1273 are helping to reduce the spread of COVID-19 around the world. However, the health crisis will not end until children can be protected along with adults. This makes Moderna's new pediatric vaccine study an important step toward an eventual end to the coronavirus pandemic.