Three in five pupils in England missed some lessons in the autumn term due to Covid-19 despite schools being open, figures show.
Children missed one additional week of schooling between September and December on average compared with previous years, according to data from the Department for Education (DfE).
Historically, between 4% and 5% of school is missed due to absence during the autumn term, but in autumn last year an additional 7% of sessions were recorded as missed due to circumstances related to coronavirus.
This represents an additional 33 million days, or five school days per pupil, the DfE analysis says.
It found that 60% of pupils had some period during the autumn term in 2020 where they did not attend in circumstances relating to Covid-19.
The figures come after heads have warned that the education recovery for children who have missed out amid Covid-19 “cannot happen on the cheap”.
School leaders’ union NAHT is calling for “significant” new investment from the Treasury for recovery work to ensure the life chances of young people are not harmed at a critical time.
All schools and colleges in England fully opened in September, but many pupils were forced to self-isolate due to Covid-19 cases in the autumn term.
Education Secretary Gavin Williamson threatened to take legal action against Greenwich Council in south-east London if it failed to keep its schools open to all pupils until the end of term in December despite a rise in Covid-19 cases across the capital.
The overall absence rate across state schools was 4.7% in the 2020/21 autumn term, which is similar to 2019/20 (4.9%) – but the figure does not include sessions missed due to Covid-19 (an additional 7%).
The analysis suggests the attendance rate has remained stable for a number of reasons – including restrictions on travel and medical appointments and fewer cases of seasonal respiratory illnesses amid the pandemic.
But the number of secondary school pupils who were persistently absent – where they miss 10% or more of their possible sessions – was higher in the autumn term 2020/21, compared with the previous year.
The rise is driven by illness absence as well as “other unauthorised reasons”, according to the analysis.
Prime Minister Boris Johnson has already made £1.7 billion of catch-up funding available in England to help children who have faced disruption from school and college closures due to Covid-19.
The Government’s education recovery commissioner, Sir Kevan Collins, is considering long-term proposals to address the impact of Covid on children.
Geoff Barton, general secretary of the Association of School and College Leaders, said: “These figures show what we already know – that the autumn term was an extremely turbulent period, with pupils regularly having to self-isolate because they either contracted Covid or were in close contact with someone who tested positive.
“This difficult situation was compounded by significant problems early in the term obtaining Covid tests for pupils and staff and in obtaining public health support in handling positive cases.
“The Government’s refusal to give schools any flexibility to finish in-school teaching early before Christmas, which was accompanied by threats of legal action, made matters even worse.”
He added: “The Prime Minister’s former senior adviser spoke yesterday of the Government’s shortcomings in the handling of this crisis, and it is certainly the case that schools and colleges were badly let down by Government leadership during the autumn term.”