Global disease experts say little is known about China's experience with long-term COVID effects thought to have afflicted millions with debilitating fatigue, brain fog and other symptoms
The company said it planned to submit the data to US, European and other regulators soon.
Moderna said the data showed two 50 microgram doses of the vaccine, half the strength of the doses used in the vaccine given to adults, generated virus-neutralizing antibodies in children.
The majority of side effects were mild or moderate in severity, the company said. The most common solicited adverse events were fatigue, headache, fever and injection site pain.