Pfizer says its COVID-19 vaccine is 100 percent effective in teens between the ages of 12 and 15, according to late-stage trial data. The company says none of the teens given the vaccine during the trial became infected with COVID-19, while 18 teens in the placebo group were infected. Pfizer will now seek approval from the FDA to offer the vaccine to teenage children, possibly in time for the new school year in the fall. Last week, the company launched another vaccine trial test for children ages 6 months to 11 years.