Shares of Novavax Inc. gained 0.6% in trading on Monday after the biotechnology firm said it has expanded its Phase 3 clinical trial for its COVID-19 vaccine candidate to include 12 to 17 year olds in the U.S. Novavax’s experimental vaccine is currently being tested in a late-stage trial that began in December in the U.S. and Mexico. The pediatric arm aims to enroll 3,000 teens. Novavax’s stock is up 112.5% so far this year, while the broader S&P 500 has gained 11.3%.

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