Funding for this research was provided by:
Engineering and Physical Sciences Research Council (EP/S022244/1)
Medical Research Council (MR/V038613/1, MR/V009761/1)
Received: 19 February 2021
Accepted: 21 April 2021
First Online: 7 June 2021
Ethics approval and consent to participate
: The data were supplied by the Department for Education under strict data protection protocols agreed between the University of Warwick and the Department for Education. The ethics of the use of these data for these purposes was agreed by the Department for Education with the Government’s SPI-M(O)/SAGE committees.
: Not applicable.
: The authors declare that they have no competing interests.