Very few things, if any, can be considered 100% effective and the vax is not a cure all, but a good way to possibly prevent catching the virus and if a vax person does, the effect is far less devastating than a non vaxed person winds up with.
But vaxed people can still catch the virus but have a better chance not to than a non vaxed person when breathing in contaminated air.
Non vaxed make up most of the deaths from the virus .
Some masks protect the wearer from breathing out and/or breathing in contaminated air..
But most cloth masks are only effective keeping the wearer from contaminating others with their breath. They don't prevent being infected by someone who have Covid 19 and breaths out the virus particles
So in essence wearing a cloth mask is for the protection of others in case you're infected , even if slightly, and trying to be a good neighbor .
Sometimes the symptoms can be real mild and you won't know you have it, but if someone catches it from you, what they caught from you might just be life threatening.
The majority of masks worn are more about protecting others while receiving the vax is more about protecting yourself.
Receiving the vax does afford protection, but not 100% worth.