WASHINGTON, United States (AFP) — Pfizer and BioNTech said Monday their Covid-19 vaccine remained 100 percent effective in children 12 to 15 years old, four months after the second dose. The companies said that the new data, which involved 2,228 trial participants, will help support their applications for full approval in the United States and worldwide. No serious safety concerns were observed in individuals with at least six months of follow-up after the second dose. […]