In most case, It is required to reboot your Host and you can find it in "Summary" tab of your Host.
In my opinion it's better to reboot Host ...
Every VIB contains a flag if Reboot is required or not. So it depends on how many VIBs (Patches) you try to installed and if its more a core component or just a 3rd party plugin like Dell OMSA for example. Murphys law will show you that always a reboot is needed and that will triggert by VUM.