After being safely administered to millions of adults around the world, new data shows that the Pfizer/BioNTech vaccine is effective in teenagers as well. A US trial of more than 2,000 12-15 year olds found that the vaccine had an efficacy rate of 100% and produced a strong antibody response, according to a press release from Pfizer. That’s good news, as children will eventually need to be vaccinated to prevent infection, says pediatrician James B Wood.