Moderna says its vaccine is safe and effective in adolescents

In a Phase 2/3 trial of 3,732 children ages 12 to 17 in the United States, blood tests showed that the vaccine produced an immune response that was equivalent to earlier findings in adults. The trial wasn't designed to look specifically at efficacy. However, initial observations found that none of the children who received the vaccine got sick with Covid-19 starting 14 days after their second dose. Four of the children who received the placebo tested positive for Covid-19, which Moderna says is "consistent with a vaccine efficacy of 100%." The company notes that figure could change as more data is collected. In the trial, a case was defined as someone who had at least two coronavirus symptoms or one symptom and a positive Covid-19 test.