Moderna begins testing its COVID-19 vaccine in babies and young children

• Moderna has begun testing its COVID-19 vaccine in children between 6 months and 12 years old.
• It plans to enroll 6,750 participants in the US and Canada in the trial.
• Getting children vaccinated is crucial to reaching herd immunity, according to Dr. Anthony Fauci.

Moderna has begun testing its COVID-19 vaccine in young children.

The biotech firm announced Tuesday the first participants in a study of children between 6 months and 12 years old received a dose of its COVID-19 vaccine. Moderna collaborated with the National Institutes of Health and the Biomedical Advanced Research and Development Authority on the study.

Moderna plans to enroll 6,750 participants in the US and Canada in the trial, called the KidCOVE study. Researchers will evaluate the safety of the two-dose vaccine given 28 days apart.

The US has not approved a COVID-19 vaccine for people under 16 years old. Researchers prioritized adults in initial vaccine trials, as severe COVID-19 illness in children is rare.

According to Cleveland Clinic, clinical trials in children differ from those in adults because of the increased layers of protection - both parents and children must agree to participate. Immune systems also vary depending on the age of the child, resulting in more complex trials relative to adult studies.

"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 Stéphane Bancel said in a press release.

The US, which is averaging roughly 2 million administered doses per day, has sped up the vaccine rollout over the past month. About 27.5% of the adult population has received at least one vaccine dose, according to the Centers for Disease Control and Prevention, and the vast majority are showing up for second shots. President Joe Biden has promised to make every adult eligible for a vaccine by May 1.

But getting children vaccinated is crucial to reaching herd immunity, Dr. Anthony Fauci told ProPublica. Fauci said he expected children to start getting COVID-19 vaccines by the time school starts in September.

"I would think by the time we get to school opening, we likely will be able to get people who come into the first grade," Fauci said.