A vaccine can only be as effective as the immune systems that it primes for any given infective agent. Respiratory RNA viruses very rarely, if ever, result in lifelong sterilising immunity. SARS-CoV-2 is no different.

If going through a disease caused by a certain virus can result in lifelong immunity, so can a vaccine designed against that virus. If going through another disease caused by a different virus leaves the host at risk of eventual (usually milder or even asymptomatic) reinfection, that's the most any vaccine can achieve.