Rich nations must delay their plans to vaccinate their children and teenagers against Covid-19 and instead donate the jabs to low-income countries, the World Health Organization (WHO) said. "In a handful of rich countries, which bought up the majority of the vaccine supply, lower risk groups are now being vaccinated," WHO director-general Dr Tedros Adhanom Ghebreyesus told reporters at a virtual conference in Geneva on Friday. "I understand why some countries want to vaccinate their children and adolescents, but right now I urge them to reconsider and to instead donate vaccines to Covax," Ghebreyesus said. The statement comes as, last week, the US, Canada and Switzerland laid out plans to begin coronavirus vaccine shots for adolescents.