[1] Univ Exeter, Med Sch, Hlth Econ Grp, Magdalen Rd, Exeter EX1 2LU, Devon, England
[2] Univ Exeter, Med Sch, NIHR Appl Res Collaborat ARC South West Peninsul, Exeter, Devon, England
[3] Univ Plymouth, Fac Hlth, Sch Hlth Profess, Plymouth, Devon, England
[4] Bournemouth Univ, Fac Hlth & Social Sci, Bournemouth, Dorset, England
[5] UCL, Dept Neuroinflammat, Fac Brain Sci, Biomed Res Ctr,Queen Sq Multiple Sclerosis Ctr,UC, London, England
[6] Univ Coll London Hosp, Biomed Res Ctr, Natl Inst Hlth Res, London, England