Schools are now the fourth-most often reported source of coronavirus infections and the number of pupils picking up the virus is increasing, broadcaster NOS said on Tuesday.

Schools have now overtaken nursing homes as a source of infection, figures from public health institute RIVM show.

And with the decline in positive tests is stagnating, some experts are saying more needs to be done in schools. For example, paediatrician and epidemiologist Patrica Bruijning has suggested introducing class by class testing and variable school hours as ways of reducing the risk of infection.

But school heads have dismissed Bruijning’s ideas, which she outlined in a television current affairs show on Sunday.  And the secondary school association VO Raad has called on experts to ‘share their insights with the government’s Management Outbreak Team, not via the media.’

By going public, experts are ‘creating unnecessary unrest and delivering more questions than answers’, the association said in a statement on Twitter.

Both prime minister Mark Rutte and the OMT have said schools are too important to close, both for pupils and parents.

A number of schools have closed their doors for a temporary period because of rising infection rates.

Pupils and teaching staff have also been urged to wear masks while moving about school buildings but not while seated during lessons themselves. Masks are set to become compulsory from December 1.

Broadcaster NOS reported later on Tuesday that the OMT is looking at extending the length of the school Christmas holidays as an option.