Coronavirus does not spread widely in schools, according to a major study being considered by Government advisers.
The research looked at 18 infected teachers and students in 15 schools and found that despite them coming into contact with 863 people at the schools, only two had been infected.
It is the only major study of transmission among children and teachers and shows that the spread of the virus is "limited" in classrooms.
Previous studies have suggested that younger children are likely to only contract a mild form of coronavirus and do not play a major role in the spread of the disease, but this is the first time the spread of Covid-19 in primary and secondary schools has been directly studied.
It comes as the Government is locked in a battle with teaching unions over plans for primary school children in reception, Year One and Year Six in England to return from June 1.
Union bosses have insisted classrooms will not be safe and ordered their members not to "engage" with the plans, while some Labour councils have also said they will refuse to reopen schools.
On Sunday, Michael Gove sought to reassure teachers and parents, insisting that the "clear scientific and clinical advice" was that it was safe for schools to reopen so long as social distancing was enforced.
"Children only have one chance at education. Over the last decade we have made significant strides in closing the gap between the richest and poorest in our schools. This lockdown has put that at risk," the Chancellor of the Duchy of Lancaster told the Andrew Marr Show.
"If progressive countries like Denmark can be teaching children and have them back in schools, then so should we. The whole point about being a teacher is you love your job. It is a mission, a vocation, to be able to excite young minds."
Dr Soumya Swaminathan, the World Health Organisation's chief scientist, also said on Sunday that "there have not been big outbreaks in schools" and the early results of studies are "very reassuring".
She said "the risks to children are extremely low with this infection, and there have not been many cases described of children transmitting it to others, particularly within school settings".
Dr Swaminathan added that, from what is currently known, it appears that "children are less capable of spreading it even if they get the infection, and certainly are at very low risk of getting ill from the disease".
The latest study, carried out in Australia, is now being considered by Government advisers as they consider how to get children back into classrooms safely.
Speaking to The Telegraph on Sunday, a senior member of the Sage sub-committee on schools, known as the Children’s Task and Finish Working Group, confirmed that the Australian study had been looked at by Government scientific advisers.
The source described it as "a very useful and interesting piece of research". The Telegraph also understands that Sage, the Government's scientific advisory group, is preparing to publish its own evidence in the coming days which will set out the thinking behind recommending that schools reopen gradually.
The study examined by the Government advisers was conducted by Australia's National Centre for Immunisation Research and Surveillance. It was cited by Australian officials when they announced that children should return to the classroom, and found schools had a "very limited" role in the transmission of coronavirus.
The scientists found that, across 15 schools in New South Wales, 10 secondary and five primary, 18 people – nine teachers and nine students – had confirmed coronavirus.
Of the 735 students and 128 staff who were in close contact with the virus carriers, only one secondary school pupil had caught it from another student and one primary school pupil from a teacher, as shown in the graphic below:
It is believed to be the only study to look at transmission in primary schools, as the swift and unprecedented closure of classrooms across the world meant there have been limited research opportunities.
The authors said their findings "do suggest that spread of Covid-19 within NSW schools has been very limited" and transmission "appears considerably less than seen for other respiratory viruses, such as influenza".
They concluded that the data "suggest that children are not the primary drivers of Covid-19 spread in schools or in the community. This is consistent with data from international studies showing low rates of disease in children and suggesting limited spread among children and from children to adults".
While Australia has a hotter climate than Europe, which some scientists believe may play a part in lower levels of infection, the findings have been backed by early data from countries such as Denmark and Norway, which shows that the reopening of schools has not led to a spike in the disease.