Funding for this research was provided by:
Wellcome (WT107496/Z/15/Z, WT104908/Z/14/Z)
Received: 21 January 2021
Accepted: 20 March 2021
First Online: 7 April 2021
: The study was approved by the University of Oxford Medical Sciences Inter-Divisional Research Ethics Committee (23/06/2016, Ref: R45358/RE001); it is being overseen by a Data Monitoring Committee at each stage of the process, and it is being conducted in accordance with the principles of the Declaration of Helsinki. Participants reporting psychological distress on questionnaires will be managed within the study risk and safeguarding protocol. Consent at the school level was obtained from head teachers. Teacher, parental/caregiver and child assent were also obtained.
: Not applicable
: The authors declare they have no competing interests.