Around 86 per cent of pupils enrolled went to their state school in England last Thursday — down from more than 89 per cent the week before, Department for Education (DfE) data show.
Nearly two in three secondary schools in England had at least one pupil self-isolating at home on 12 November, according to the figures.
In secondary schools, attendance was around 83 per cent last Thursday, compared to 87 per cent on 5 November.
Overall, approximately 6 per cent to 8 per cent of state school pupils did not attend school for coronavirus-related reasons on Thursday last week, the analysis shows.
The DfE said the drop in state school attendance was “mainly due to the increased number of pupils self-isolating due to potential contact with a case of coronavirus”.
Schools have remained open during England’s second lockdown over coronavirus, compared to spending more than two months open to only vulnerable children and those of key workers during the first one.
Paul Whiteman, the general secretary of school leaders’ union NAHT, said: “The government is quite correct to put a high priority on preserving young peoples’ education.”
However, he added: “The drop we have seen in attendance in secondary schools this week in particular is a real cause for concern.
“We remain very concerned about the spread of the virus, particularly amongst older pupils and in secondary schools.”
A DfE spokesperson said: “Over 99 per cent of schools have been open every week since term began and millions of pupils are continuing to benefit from being in school.
“The Chief Medical Officer remains of the view that schools should remain open, and has highlighted the damage caused by not being in education to children’s learning, development and mental health.”
Additional reporting by Press Association