Calls for face masks in schools to return have escalated as fears grow over “sky-high” COVID cases in Indian variant hotspots like Bolton.
The B1.617.2 variant, which is thought to affect children more, has seen a sharp rise in several areas of England.
This has prompted calls for secondary school pupils to wear face masks in classrooms again after the government removed the mandate earlier this month.
Professor Christina Pagel, director of University College London's Clinical Operational Research Unit, warned on Tuesday that the current measures in schools are not enough to protect against the risk of the virus.
In a long Twitter thread, Pagel said lateral flow device tests - now the government’s main mitigation in secondary school - are "not really being done”.
She also highlighted how cases in secondary school-age children in Bolton are “sky high,” with over 1% of 10-14 year-olds testing positive last week and the week before.
“Where cases are high in the community, schools are at risk of outbreaks," she said. "Particularly with this new variant, which is likely more transmissible."
Pagel then called an "improvement to mitigations" having tweeted two days earlier that the government should be reintroducing masks in schools.
Meanwhile, Manchester mayor Andy Burnham announced on Tuesday that a formal request had been made to the government to allow schools discretionary power to reintroduce face coverings.
He told a press conference: "We are being told by the Department for Education at a national level that there can be no deviation from the national position on schools vis-a-vis the roadmap - where it is being said now that schools should not enforce or require the wearing of face coverings within school.
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"Now, not just in Bolton, but certainly in Bolton, there are schools there and across Greater Manchester that obviously are looking at the local situation and wanting to apply local discretion as to the situation within their school, within their community, and that is entirely understandable and right in our view."
Other scientists have also criticised the removal of mitigations in schools as well as Public Health England's failure to publish school data on the mutant strain in both its May 13 and May 22 report.
Dr Zubana Hague, a member of Independent Sage, cited data from the report’s findings showing vaccines are just 33% effective against the Indian variant after one dose. "That leaves 60% of adults and all children still at risk," she said.
She wrote on Twitter: "Boris Johnson said he sees no current signs of having to 'deviate' from plans to scrap the last lockdown curbs yet both he and PHE were fully aware of all this alarming data.
“They are also holding back important data on number & extent of school outbreaks re: #B16172,” she added.
“And of all the action the govt could have taken immediately after May 17 reopening to curb the *rapid spread* of #B16172 India variant, the easiest/most politically-feasible thing to do would have been to RETAIN #facemasks in secondary schools. But instead, they scrapped it."
Deepti Gurdasani, a senior lecturer at Queen Mary’s University London, also tweeted that the PHE report looked "seriously worrying" and criticised the fact it contained no data on schools.
She said: "It's bizarre we're continuing re-opening and removing school mitigations as we see exponential growth in many parts of England."
It comes as the government has been accused of creating confusion by changing its COVID guidance for those living in eight areas of England worst affected by the Indian variant without any widespread announcement.
People have been told to avoid non-essential travel into and out of the areas, which include Bolton and Blackburn with Darwen.
They’ve also been told to keep two metres apart and meet outside rather than indoors “wherever possible”.
Meanwhile, the latest Department of Education data shows a 33% increase in the number of school pupils testing positive for COVID on May 20 compared to the week before.
There were 18,000 pupils who were absent from school because they suspected they had COVID-19, - up from 17,000 on May 12, and 4,000 were off after testing positive - up from 3,000.
The data also suggests that 82,000 pupils were out of class and self-isolating on Thursday last week due to potential contact with a case of coronavirus, compared to 65,000 the previous week.
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Paul Whiteman, general secretary of school leaders’ union NAHT, said: “There is growing concern about the spread of the Indian variant in schools. The Government must make the data they hold on this public without further delay.
“Schools need transparency about the levels of infection around the country so they can make sure they have the right measures in place for their local area.
“The Government must be proactive to ensure that transmission in schools, particularly in relation to the new variant, is not allowed to proceed unchecked.”
Yahoo has contacted the Department of Education for comment.
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