The US Centers for Disease Control and Prevention on Friday issued new guidance for US schools to reopen, recommending universal mask-wearing and physical distancing as key Covid-19 mitigation strategies to get children back in the classroom quickly.

The guidelines which also emphasise the need for facility-cleaning, personal hygiene and contact tracing, are intended to give school districts a road map to bring the nation's 55 million public school students back to classrooms without sparking Covid-19 outbreaks.