Almost nine in 10 secondary schools in England had no coronavirus cases after they reopened, official figures suggest.
Surveillance data showed only nine of 80 schools surveyed had spotted one infected pupil or staff member in the fortnight ending March 31. Four saw at least two cases, according to the Office for National Statistics report.
Almost 10,000 secondary teachers and pupils were swabbed for the study, which is carried out regularly to track the spread of the disease in schools.
Just 0.34 per cent of pupils tested positive — compared to 1.2 per cent in December, when Covid was spreading rapidly in the community. Only one in every 500 teachers were infected in the last round of testing, down from one in 60 before Christmas.
Public Health England bosses said the data was ‘reassuring’.
It comes after teaching unions warned Number 10’s ‘big bang’ reopening of schools on March 8 — the first step in the ultra-cautious roadmap back to normality — was ‘madness’ and risked an explosion in cases.
Unions called for year groups to be sent back in phased stages, claiming the mass return could put teachers at risk from the virus.
Office for National Statistics testing was carried out in 80 schools. Statisticians warned it was not directly comparable to the country because they focused on areas with the highest infection rates in September
England reopened secondary schools to all pupils on March 8 in the first stage of Boris Johnson’s ultra-cautious roadmap out of lockdown
MOST BRITONS ARE STILL COMPLYING WITH SELF-ISOLATION RULES, SAYS SURVEY
More than 85 per cent of infected Britons are self-isolating, official figures suggest.
Office for National Statistics workers surveyed more than 1,000 adults who had recently tested positive for the virus over the five days to April 16.
They found almost nine in ten said they were sticking to the ten-day self-isolation rule, helping to curb the spread of the virus in the community.
But experts warned this figure was likely a huge over-estimate because it was based on self-reporting with participants not asked to provide evidence they had stayed at home.
They pointed to other studies suggesting fewer than half of Britons asked to self-isolate were actually doing so.
The Government has made it illegal not to follow self-isolation rules, putting extra pressure on people to claim they are following the rules.
The estimated high levels of self-isolation come amid a successful vaccination programme, which by April 16 had jabbed more than 32million Britons – or three in five adults.
Pubs, restaurants and cafes were also permitted to reopen for outdoor seating on April 12, inside this reporting period.
Dr Shamez Ladhani, a PHE epidemiologist and the study’s chief investigator, said: ‘Results of this study shows current Covid infection among secondary school staff and pupils has fallen significantly from the already low levels recorded last November.
‘These findings are reassuring and contribute to wider evidence that shows the risk of transmission in schools is low.
‘This also indicates the importance of public health measures in schools for reducing transmission.’
Fiona Dawe, deputy director of wider surveillance studies at the ONS, said: ‘The data shows that during round four of testing, there was a reduction in current infection rates in schools taking part in the study.
‘In secondary schools, there was a significant reduction in current infection levels in both pupils and staff.
‘As we see the vaccine rollout across the country, it’s essential we continue testing for Covid infection and antibodies in school settings.
‘The Schools Infection Survey remains an important study in assessing the role of schools in the pandemic and how the virus is transmitted in school settings.’
The ONS report, carried out alongside experts at the London School of Hygiene and Tropical Medicine and PHE, tested 7,156 pupils and 2,645 secondary staff members between March 15 and 31.
Schools were based in 14 authorities where Covid cases were highest in September, such as Bolton, Knowsley and Manchester city.
Participants were offered the gold-standard PCR test, which studies show is the most accurate at diagnosing Covid infections even when someone has no symptoms.
The scheme — Round 4 of the Covid School Infection Survey — was done separately to the mass roll-out of lateral flow tests.
Pupils and staff are asked to swab themselves twice a week, in order to hunt out any cases of the virus before the have chance to spread in classrooms.
ONS experts warned the figures were not directly comparable to England because they focused on areas that had high rates last year before the second wave started to take off, rather than a representative sample.
They also did not say whether participants were tested regularly over the two-week study period or just once.
The ONS found 0.34 per cent of secondary school pupils tested positive (or 24 pupils), and 0.19 per cent of staff members (or just five teachers)
They above shows the percentage of secondary school pupils and staff testing positive in the two weeks to March 30 was lower than in November and December
Results showed 0.34 per cent of pupils in secondary schools tested positive for the virus (or just 24 children). But among teachers only 0.19 per cent had the virus.
Infection rates were both lower than those picked up in November and December during rounds one and two, when more than one per cent had the virus.
The ONS also rolled out the programme to primary schools, testing 3,718 pupils and 1,343 staff members.
But they found so few had the virus that they had to suppress the numbers.
The ONS has published no data for round three of the study.
Covid cases did rise slightly in younger age groups after schools went back in early March, mass swabbing revealed. But experts said this was nothing to worry about because it was expected when more people began to mix.