Nearly a year ago I came across research from New Zealand showing children didn’t infect their teachers with Covid-19.

And now, Scottish research shows they not only don’t pass Covid on to their parents, they protect them from it.

The study of more than 300,000 adults suggests the risk of testing ­positive for coronavirus is lower for adults living with a child up to the age of 11 than those without children even when schools are open.

What’s more, the risk is lower still for adults who live with two or more children under 11 years old.

So it seems the opposite of what people have been saying about children carrying Covid is true – they may provide a protective effect against Covid infection in their families, and probably their teachers too.

Dr Rachael Wood, clinical lead for maternal and child health at Public Health Scotland and an author of the study, believes children play little role in the transmission of Covid.

We know children are far less likely than adults to get severely ill with Covid, but we don’t fully know why.

Dr Wood says: “More work is needed to explore the idea that living with children might offer adults protection from infection, but what we can safely say is that children are not major drivers of Covid-19 transmission.”

Researchers at the University of Glasgow and Public Health Scotland examined data from all NHS Scotland healthcare workers and their household contacts between March and October 2020 to assess the effect of living with young children on Covid-19 risk.

Commenting on the findings, the Scottish Tories said the results suggest students could have been brought back to classrooms sooner.

“The SNP Government were slow to accept our calls for voluntary testing of all pupils, but have at last rolled this out to make our schools as safe as possible,” said Conservative education spokesman Jamie Greene.

“We have proposed a Covid catch-up plan for our pupils who have had so much disruption over the last year. However, this study suggests that they could have been brought back quicker, without posing any greater risk to their household or the wider community.”

A Scottish Government spokesman said: “This study adds to the ongoing Covid research which informs Scotland’s response to the global pandemic.

“It is encouraging, as we seek to return children and young people to education, that those in this study living with children were at less risk.”