Local public health directors are advising schools not to follow the government's plan to use rapid Covid tests to keep close contacts of coronavirus cases in the classroom.
The Department for Education has said schools should give pupils and staff who have been in close contact with Covid cases a daily test for seven days and keep them in school if the results are negative, instead of sending them home to self-isolate.
However, some local directors of public health are advising schools in their areas against following the DfE's plan because of concerns that the tests are unreliable.
Tes has seen statements from several directors of public health advising schools not to use these tests to keep Covid contacts in school.
The news is another major blow to a key plank of the government's strategy for reopening schools safely.
It was reported last night that the Medicines and Healthcare products Regulatory Agency (MHRA) has told the government it had not authorised the daily use of the 30-minute tests in schools because of concerns that they give people false reassurance if they test negative.
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Statements provided to Tes by the NEU teaching union show that public health directors have advised schools in their areas not to use the tests to keep contacts of Covid cases in schools.
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In Essex, the public health director told schools: "Daily testing of contacts of known positives in schools is not an appropriate alternative to requiring self-isolation."
The public heath director for Cambridgeshire and Peterborough, Liz Robin, said: "Some directors of public health, including myself, are concerned that using lateral flow tests in this way could increase the risk of transmitting Covid-19 infection in school, at this stage of the pandemic when rates of Covid-19 are high.
"This is because lateral flow tests don’t identify all cases of Covid-19 – there are some ‘false negative’ results."
The advice to schools adds: "I would recommend against local schools starting daily LFT ( lateral flow test) testing of pupils and staff who are close contacts, until the evidence is clearer."
The public health director for East Berkshire, Tessa Lindfield, told schools: "Questions remain about the reliability of the LFTs, which may miss some infections and schools may wish to conduct individual risk assessments on the use of testing to release contacts of people with confirmed Covid.
"My preference at this time is that contacts isolate for the required period rather than use repeat testing to enable them to return to school."
And the local public health team in Thurrock told schools that lateral flow device tests fail to detect between 23 per cent and 53 per cent of people infected with Covid-19.
They added: "We are concerned that the low accuracy of LFD tests may give a negative result in close contacts who have actually been infected."
The advice says: "Our recommendation to you is that you do not undertake daily testing of close contacts of infected children using lateral flow services to allow them to remain at school. We recommend that any close contacts of infected children be asked to self-isolate for 10 days in line with the previous protocol."
Jules White, headteacher and the leader of the WorthLess school funding campaign group, has said some schools are unwilling to use rapid lateral flow tests in the way recommended by the DfE.
Mr White said: "We are working on the testing now but we are not going to do the serial testing of close contacts of Covid cases until we see reliable evidence that this test can be relied upon to identify Covid cases because there are concerns that it can't. We will still be sending close contacts home to self-isolate."
The public health directors' advice to schools comes as academics warn that the testing strategy proposed by the government could actually increase Covid-19 in schools by allowing undetected cases to remain in classrooms.
Robin Bevan, the NEU's president said: "As a headteacher, with a relevant academic background, the recommendations around LFTs have concerned me from the outset, because the scientific evidence does not support it.
"As a trade unionist, those concerns extend to our members, their safety and the safety of all in our communities. The DfE has – on more than one occasion – disregarded the scientific evidence when making decisions about school operations. This is among the most egregious of those instances."
The DfE's plan to use lateral flow tests in schools was announced at the end of last term but is still in place despite the national lockdown.
In a daily bulletin sent to secondary schools on Wednesday, the department said schools should now use the lateral flow test to offer:
- Initial testing of vulnerable pupils and children of critical workers who are on school and college sites (two tests, three to five days apart).
- Weekly testing of staff who are on school and college sites.
- Daily testing of close contacts of positive cases in school and college as an alternative to self-isolation.
Geoff Barton, general secretary of the Association of School and College Leaders, wrote to education secretary Gavin Williamson asking for the scientific basis for using lateral flow tests instead of asking contacts of Covid to self-isolate, but has not yet had a reply.
He said: "Our understanding is that lateral flow tests produce a number of false-negative results and we are concerned this will mean close contacts being in school who have tested negative but are in fact positive, whereas under the system of self-isolation they would not be in school.
"It seems counter-productive if this means there are more positive cases in school than previously as this will potentially mean more transmission of the virus and more disruption. Our question is how the use of lateral flow tests in this way is safer and more effective than the use of self-isolation.
"We are waiting for an answer from the government and believe it is vital it provides this information urgently.”
'Unreliable and impossible'
Another school leader has warned that the government's plan is both unreliable and practically impossible.
Catharine Darnton, the headteacher of Gillotts School in Henley-on-Thames, said: "I have been concerned since the first communication we had from the department said that even if people had a negative test, they should still abide by social distancing because that is not possible in classrooms.
"And I became more concerned at the reports from Liverpool and Birmingham University where cases of Covid were missed using this test.
"There is a question about why schools are the only area of life where it is being proposed to use these tests in this way to replace the need for Covid contacts to self-isolate."
She also warned that the testing plan placed an impossible demand on schools.
"Even if the tests were reliable, what schools are being expected to do is actually impossible. The serial testing of close contacts is supposed to happen before the start of the school day," she said.
“One pupil in Year 10 who has different subject options can have 70 close contacts. How does a school test that many people at the start of a day when we are told it we can only get 10 tests done in an hour per each testing station?
"Each station needs a test processor, plus you need a test assistant for every couple of stations. So if a secondary school had six stations, you could do 60 tests in an hour.
"But the stations need to be 2m apart so that needs a really big space. And how do pupils come into school early for this to happen when they come in on the bus?”
The DfE has been approached for a comment.