Schools that practice social distancing, mask-wearing and other precautions have not seen rapid spread of coronavirus, but indoor sports activities should be avoided, researchers said Tuesday.

The researchers from the US Centers for Disease Control and Prevention (CDC) reviewed studies of school settings in the United States and other countries.

"As many schools have reopened for in-person instruction in some parts of the US as well as internationally, school-related cases of COVID-19 have been reported, but there has been little evidence that schools have contributed meaningfully to increased community transmission," they wrote in the Journal of the American Medical Association on Tuesday.

"The preponderance of available evidence from the fall school semester has been reassuring insofar as the type of rapid spread that was frequently observed in congregate living facilities or high-density worksites has not been reported in education settings in schools," they said.

They said the data suggests a path forward to "maintain or return primarily or fully to in-person" instruction.