“…Other barriers to PrEP adherence at service user level included medication concerns, for example the pill being too big or tasting unpleasant, [108] missing clinics, [109] forgetting to take medication [54,75,103,110] and cost [111,112]. Disruption in routine was also reported [54,93,103,108] but Vaccher et al [103] stated that this could be reduced by carrying spare medication for emergencies. Certain service user groups were identified as being at risk of low PrEP adherence, including those from ethnic minorities, [73,91,111] young MSM, [91] smokers, [111] and those with problematic alcohol or substance use, [91] all of which are exacerbated by systemic disadvantages within society or from an individual's predisposition to risky behaviour.…”