WASHINGTON, United States (AFP) — Moderna said Thursday its Covid-19 vaccine is 96 percent effective among youths aged 12 to 17, according to the results of its first clinical trials. Two-thirds of the 3,235 participants in trials in the United States received the vaccine and one-third were given a placebo. The study “showed vaccine efficacy against COVID-19 of 96%; mRNA-1273 was generally well tolerated with no serious safety concerns identified to date,” the company said. […]