are macks immune from viruses and adware problems

   I am sure some Mac users would say yes.
   You could have asked if Macs get viruses or adware.  A Mac user could answer that.
   But you asked if they are immune from viruses and adware.  The real argument about Mac and other nonWindows software/operating systems not being as susceptible to viruses and adware is that they are not as popular and so not attacked as much.  This does not mean that they are immune.  My opinion is that they are not immune.