Practical experience has ...

Practical experience has shown that bacteria can grow through RO membranes and due to the size will not remove viruses due to pore size.  They will reduce bacterial numbers so disinfect but the higher the numbers before the membrane the more will be found afterwards.  UV after the membranes will inactivate viruses and again reduce bacterial numbers but unless a material such as chlorine is used after that there is nothing to prevent growth of bacteria after UV.  Neither RO nor UV have a residual effect.  It does depend on what you are trying to achieve.