China's state-run Global Times pushed back against complaints of opaque testing and dubious effectiveness for Chinese coronavirus vaccines by touting Sinovac as the "world's first to release relevant data of ongoing trials on infant and teenage participants." According to Sinovac medical director Zeng Gang, trials on young patients have been proceeding smoothly, with few safety concerns: So far, the vaccine is generally safe for 72 adolescents in phase I and 480 in phase II of the trials conducted in China, with an overall adverse reaction rate of 23.7 percent to 29 percent, but mostly mild reactions, Zeng suggested, adding that only two children, aged three and six respectively, reported fever after the shots. Groups getting different dosage in controlled trials have all produced a qualified immune response to the vaccine.