Almost 1,000 children were diagnosed with Covid in the capital last week, with the infection rate in the 10-14 age group more than double than at the start of the new school term last month.
It comes as experts called for the reintroduction of masks in secondary schools, amid warnings that teenage infections were “spilling over” to parents.
One school in Haringey has reintroduced bubbles and shared updated information from the borough’s public health chiefs, which stated: “Siblings of children showing symptoms should also be tested (PCR) and remain at home until results are returned.”
Haringey council confirmed “additional temporary preventative measures” are being put in place in schools to control an outbreak.
One primary in Walthamstow has activated part of its “Covid outbreak” plan, including enhanced cleaning and the use of bubbles at breaks and lunchtimes. At least one Year 3 child tested positive and parents with children in the same class were urged by Waltham Forest council to give their child a PCR test.
The school said it may consider limiting parental access and reintroduce masks for adults in communal areas.
Professor Christina Pagel, of University College London, said the UK was an “outlier” in terms of Covid cases and precautions. She said cases in children were “spilling over” into parents.
“Over 100,000 children have been infected since the beginning of term,” she said.
“There is literally an outbreak in every school. 1.4 per cent of 10-14-year-olds in England tested positive last week. That is a lot of children. I think we need to put mitigations back in school, particularly masks in secondary schools.”
Serious illness remains rare in children but more than 200 were admitted to hospital in England in the first five days of September for Covid treatment.