US PresidentDonald Trumpsigned an executive order Monday pushing for a rethink ofschool vaccine mandatesand repeating calls for themeasles, mumps and rubella (MMR) vaccine to be separated into three individual shots. Curbing vaccineshas been a key priority for Health SecretaryRobert F. Kennedy Jr, who founded an anti-vaccine non-profit and has long promoted a disproven link betweenimmunisation and autism. T