<prompt> Translate the following text to EnglishKwa sababu ya gharama na ugumu wa kuweka ED, ufanisi wa jamaa na gharama ya vikao vya booster ni suala jingine muhimu linalostahili utafiti zaidi.  <response>: the costs and difficulties of the ED setting, the relative efficacy and cost of booster sessions is another important issue deserving further research. 