Iimveliso ezisebenzela iimfuno zempilo zabemi. Ngokutsho kwe-WHO, ezi mveliso kufuneka zibekho "ngalo lonke ixesha, ngamaxa afanelekileyo, kwiifom zedosi ezifanelekileyo, kunye nomgangatho oqinisekileyo, kunye nexabiso lomntu onokuthi ahlawulwe".