Funding for this research was provided by:
Medical Research Council (G0800298, G0400061)
Received: 7 June 2019
Accepted: 3 March 2020
First Online: 18 May 2020
Ethics approval and consent to participate
: All participants and their parents or guardians gave informed written consent/assent in accordance with ethics approval by the National Research Ethics Committee, Suffolk, UK.
: Not applicable.
: The authors declare that they have no competing interests.