Moderna Inc.
MRNA,
-6.19%
said Thursday that initial data from the study evaluating its COVID-19 vaccine in teens between the ages of 12 and 17 years old showed an efficacy rate of 96%, with no serious safety concerns. The Phase 2/3 clinical trial is testing the vaccine in 3,235 teens who have received at least one shot in the two-dose regimen and have not previously been infected with SARS-CoV-2. "Because the incidence rate of COVID-19 is lower in adolescents, the case definition is less stringent ... resulting in vaccine efficacy against milder disease," Moderna said in its earnings release. Pfizer Inc.
PFE,
+0.05%
is expected to have its emergency authorization for its COVID-19 vaccine expanded sometime in the next week to include 12 to 15 year olds. Data from Pfizer's study showed an efficacy rate of 100% in 2,260 teens who have had or not had COVID-19. Moderna's stock is up 55.8% for the year, while the S&P 500
SPX,
+0.07%
has gained 10.9%.